[WA] Daimler Freeline 299 - EDIT: photo links corrected

[Herbert]

Last Thursday, Dennis96 & I visited dilligaf's Daimler Freeline 299.

As I've mentioned before, during the mid- to late-1970s, Daimler Freelines repeatedly appeared on my horizon, but I only ever rode one in service. Every morning on my way to school in 1976 & 1977, I watched in envy as a Freeline stopped on the opposite side of the road to me on a school special heading for Sorrento.

I tried to recapture those memories with this view ...



... but couldn't quite make visible the Freeline's pre-selector which I used to observe through the driver's side window. A fellow student (quite obviously a bus enthusiast - where is he now?) explained to me how a pre-select gearbox worked, as we watched the driver each morning pre-select then engage 2nd gear, then pre-select 3rd (except back then I didn't know they had 5sp boxes, so I thought it was 1st & 2nd!).

Under the Freeline's "hood" is the Daimler CD650H 10.2 litre 160bhp 6-cylinder diesel - and 299's never missed a beat. Great to hear that wonderful CD650H "ducca ducca ducca" once again!



Interesting to compare the placement of the air-compressor with a Worldmaster.

Now for the "work centre" shot... I'm not too sure how original the dash layout is. The large red air, oil & water warning lamps are a definite MTT-ism - originating with either the Tiger Cubs in the mid-1960s or the Leopards in 1969. Strange that such a modification wasn't done to Worldmasters.

The row of switches are identical to an AEC, with the two dash lights (the two raised circles next to the speedo) reminiscent of a Regal VI. It retains its MTT-modified speedo with km/h for speed & MPH for the tacho.

Note the pre-selector on the right, with the indicator switch & horn on the left - plus that classic Daimler "D".



I wished I taken lesson from a contortionist before attempting this next shot! Taken particularly for RK215's benefit, it shows the gate arrangement on the pre-selector, and slightly corrects my memory of last seeing one 20 odd years ago.

Similar to an AEC pre-selector, reverse was pre-selected via 2nd gear (1st on a 4-speed) by lifting the catch/gate. If selected in a single plane, the order of gears appears to be R-2-4-N-5-3-1 - ie with the shortest "travel" between the most-oft pre-selected gears: 4th & 5th. Clever design.



Finally, the pedals. I was suprised how little travel there was on the actuator pedal, but my memory served me well: opposite to an AEC, the release of air is on the upward/engaging movement. Combined with dilligaf's description in another thread, this seems to confirm RK215's hunch that the system employed is pneumatic-over-mechanical, as opposed to a fully-pneumatic system.



Inset is 299's proof of identity - in the classic MTT style of interior fleet nos.

Now, some ancient history & theorising:

The WA Government Tramways put 20 Daimler Freeline D650HS with Howard Porter B45F bodies into service between April 1957 and May 1958. Numbered 136 to 154 in the WAGT fleet, on 30.06.1960 they became 288-307 in the MTT fleet. dilligaf's bus, 299, is right in the middle of this batch.

The MTT later acquired a further eleven Freelines: one from Riverton Bus Service and ten from Scarborough Bus Service. These became 455-465 and initially all featured bodies built by the Scarborough subsidiary, Motor Body Builders (though to two distinctly different designs). Most of this batch received complete re-bodies during the mid-1960s.

These eleven units had been delivered over a greater time period than the WAGT examples, and initially had different gearboxes. 455-461 had 5-speed mechanically-actuated pre-select boxes, 462 5-speed pneumatically-actuated, and 463-465 4-speed pneumatically actuated. During 1962 all except 458 had been converted to 5-speed pneumatically-actuated boxes.

[458 probably wasn't converted due to its impending demise in 1963, with its mechanicals being reduced to spares and its body being transferred to 462.]

It is possible that the different original gearboxes was a result of changes in Daimler's specifications during the first half of the 1950s - if I correctly recall data provided previously by RK215.

Thus, the MTT had assembled a fleet of 31 Freelines. I am not aware of any other Australian operator of Freelines, other than the sole example in Adelaide which was their Gardner 6HLW-powered No 166, subsequently owned by Board member leyland4ever.

For comparative purposes, the 22 known Australian Freelines are presented below in chassis no order. Looking at them in this manner demonstrates a distinct trend:

456 : 25020 - 02.04.1953 - 5mech - MBB B48F / BO B45FR
457 : 25049 - 05.08.1953 - 5mech - MBB B48F / BO B45FR
166 : 25055 - xx.xx.1953 - 5mech? - Lawton B42F - Gardner 6HLW
455 : 25079 - xx.02.1954 - 5mech - MBB B48F
458 : 25307 - 25.03.1954 - 5mech - MBB B48F
459 : 25406 - 20.01.1955 - 5mech - MBB B48F / HP B45FR
460 : 25408 - 23.03.1955 - 5mech - MBB B48F / HP B45FR
461 : 25409 - 20.05.1955 - 5mech - MBB B48F / HP B45FR

462 : 25570 - 07.09.1956 - 5pneu - MBB B48F / MBB B49F (ex-458)
289 : 25571 - 26.04.1957 - 5pneu - HP B45F
288 : 25572 - 09.04.1957 - 5pneu - HP B45F
293 : 25573 - 02.07.1957 - 5pneu - HP B45F
290 : 25574 - 08.05.1957 - 5pneu - HP B45F
292 : 25575 - 17.06.1957 - 5pneu - HP B45F
291 : 25576 - 23.05.1957 - 5pneu - HP B45F
294 : 25577 - 26.07.1957 - 5pneu - HP B45F
299 : 25578 - 18.10.1957 - 5pneu - HP B45F
298 : 25579 - 24.09.1957 - 5pneu - HP B45F
300 : 25580 - 08.11.1957 - 5pneu - HP B45F
297 : 25581 - 06.09.1957 - 5pneu - HP B45F
301 : 25582 - 27.11.1957 - 5pneu - HP B45F
296 : 25583 - 16.08.1957 - 5pneu - HP B45F
295 : 25584 - 01.08.1957 - 5pneu - HP B45F
305 : 25585 - 28.03.1958 - 5pneu - HP B45F
304 : 25586 - 20.02.1958 - 5pneu - HP B45F
302 : 25587 - 02.12.1957 - 5pneu - HP B45F
307 : 25588 - 13.05.1958 - 5pneu - HP B45F
303 : 25589 - 18.12.1957 - 5pneu - HP B45F
306 : 25590 - 30.04.1958 - 5pneu - HP B45F

464 : 25665 - 17.11.1957 - 4pneu - MBB B48F / BO B45FR
465 : 25666 - 08.12.1957 - 4pneu - MBB B48F / HP B45FR
463 : 25690 - 02.07.1958 - 4pneu - MBB B48F / BO B45FR

I haven't been able to find the thread where RK215 describes the development of the Freeline - I hope it isn't amongst the now "lost" posts!

Special thanks to dilligaf for arranging our visit at such short notice. Greatly appreciated.

[Swift]

Gorgeous bus and what an interesting dash!
Got any other shots of it from the outside?
I love that front wheel and it looks like it can take an AEC type nutguard judging by the 3 evenly spaced holes just inside the rim.
While on wheels,what is that style of rim called,does anyone know??I always called them the powerful wheel because they seem to only go on heavy duty buses.
I didn't know Daimler made their own engine.Love to know what it sounded like.Use a Leyland 680 as a reference to describe it!

[The Bell Tower]

ex MTT Daimler #295 has just been discovered in a caravan park on Welshpool Rd. It is drivable but unlicenced. It has been converted to a motor home. A photo later.

[RK215]

I wished I taken lesson from a contortionist before attempting this next shot! Taken particularly for RK215's benefit, it shows the gate arrangement on the pre-selector, and slightly corrects my memory of last seeing one 20 odd years ago.

Herbert - great pictures and a great post! Thanks much for doing the contortionist bit to get the preselector gate photo.

It's interesting that the "pneumatic" version of the Freeline has organ-type brake and gearchange pedals. At first glance they look like treadle valves, but a closer look suggests that they are not. The "hydraulic" Freeline had conventional pedals. I'll see what I can find out about its gearchange pedal travel.

The air compressor placement may have been something of an afterthought, as its use probably wasn't envisaged when the Freeline was designed.

The earlier Freeline information, was, I think, in the "Timeline of Adelaide Buses" thread, which seems to have disappeared. However, I have kept an .mht copy, so when I get a chance, I'll update and post here.

Cheers,

[RK215]

Regarding Freeline mechanical history, I have taken the opportunity to quickly review the various sources on hand (books, magazines, OEM literature, etc.). The following is a synopsis.

The Freeline was announced in the early part of 1951 as Daimler’s entry to the then-new underfloor-engined category. Initially it was available in two wheelbase/length combinations. The shorter, 16’4” wheelbase model was intended for the UK domestic market where 30 ft bodies were allowed. The longer, 17’6” wheelbase model was intended for the export market, accommodating bodies of 33 ft or so. At the time, 33 ft was the maximum allowed in some export markets, like New Zealand, so it was an important datum point.

The engine options were the Daimler D650H, Gardner 6HLW or Gardner 5HLW. Transmission options were the 4 and 5-speed preselectors, mechanically-operated, with right-hand gate- type selector lever. The gate-type gear selector had arrived with the CD650, although in that case it was left-hand mounted. The final drive was a left-offset underslung worm drive at 8½“ centres.

The Freeline inherited the servo-accumulator type Lockheed constant-flow hydraulic braking system that had been introduced with the CD650 model, with external wheel cylinders operating S-cam drum units. However, it did not have as standard the hydraulically-assisted handbrake of the CD650, and as far I can ascertain, this feature was not offered or fitted. On the other hand, the CD650-type hydraulically-assisted mechanical gearchange was available. Similarly, CD650-type integral hydraulically-assisted steering, operated from the same pump as the braking system, was available.

At least by late 1952, when the first Freeline was delivered to Auckland Transport Board, there had been some changes. As the first Auckland batch (of 90) was, as best I can estimate, ordered in the third quarter of 1951, it seems that these changes were made quite early on. The Auckland Freelines had the Powervalve version of the Lockheed constant flow braking system. They also had hydraulic-over-mechanical, fully-powered operation of the gearchange, 4-speed in this case. The doors were also hydraulically operated, a featured provision of the Lockheed system.

Air brakes were first offered as an option in 1952, and had become standard by 1957 or 1958.

In the latter part of 1954, a longer export version, with 20’4” wheelbase for 36 ft nominal bodies was added to the range.

In 1955, Powervalve hydraulic brakes were still standard, although the Lockheed system had been amended to delete the charging valve, which had been somewhat troublesome in the Auckland fleet (although I think still retained on the second batch). Power-assisted steering, where fitted, was still of the integral hydraulic type operated from the braking pump, which was now positively driven, rather than belt-driven.

By 1958, there were further changes. As well as 4- and 5-speed preselector gearboxes, the Daimatic 4-speed in semi-automatic or fully automatic form was also offered. The preselector gearboxes had mechanical gearchange as standard, with the option of “air assistance”. The braking system was air-pressure with diaphragm actuators, there being no mention of a hydraulic option. Air-pressure assisted steering was an option. So, by this time the Freeline could be described as all-pneumatic, in contrast to the “all-hydraulic” initial version.

Courtesy of Dilligaf, we now know that WAGT/MTT Freelines had an air-over-mechanical gearchange, and not an air-assisted mechanical gearchange. Perhaps Daimler offered both types, as it had done with the hydraulic case, although I suspect that its mention of “air-assisted” was simply a case of the wrong terminology.

Whether the pneumatic auxiliaries were available with the introduction of the air brake option in 1952 is unknown. I suspect, though, that the answer is yes, as Daimler would most likely have wanted to retain existing functionality. Since by that time the hydraulic-over-mechanical gearchange had been developed, presumably as a successor to the hydraulically-assisted mechanical type, it might have been redundant to develop pneumatic counterparts for both, in which case just the air-over-mechanical type would have been offered. This would have been simpler, and would have avoided the pedal “kickback” possible with mechanical linkages, although with the potential disadvantage that being “stuck- in- gear” was possible if the air pressure was lost. Also unknown is whether the original air brake option used piston- or diaphragm-type actuators. Daimler had previously used the piston-type in its few air-braked models, but in 1952 the diaphragm type was just appearing in British practice, the Leyland Tiger Cub being an early example so-fitted.

The air-assisted steering option seems unlikely to be a late addition. In 1956, when Daimler released its CVD/G6-30 30 ft double-decker chassis, it featured air brakes and an air-operated 4-speed preselector gearbox, but the power steering option was of the non-integral hydraulic type. Probably this combination would have been chosen for any Freeline update that took place after 1956, suggesting in turn that the air-assisted option was developed earlier on. Unknown is whether or not the air-operated 4-speed preselector gearbox developed for the CVD/G6-30 - as compared with the air-over-mechanical 4-speed type - was ever offered or fitted to the Freeline.

With the arrival of the air-operated Daimatic 4-speed gearbox at the end of 1957, Daimler had the incentive to standardize on pneumatic systems, although it probably would still have built the all-hydraulic Freeline had any existing customers so asked. So, the best guess is that the change to all-pneumatic as standard happened when the Daimatic was added to the option list.

The Freeline remained available until 1964, although very few were built in its last years.

Now for some comments and comparisons:

Daimler was a little late with the Freeline, as AEC (Regal IV), Guy (Arab UF) and Leyland (Olympic and Royal Tiger) had released their respective underfloor models in 1949 or 1950. With the D650H engine option, it did offer a power advantage, though, as compared with AEC (9.6 litre), Guy (Gardner 6HLW) and Leyland (O.600). AEC subsequently offered an 11.3 litre option for the Regal IV, and Leyland made the O.680 engine standard for the Worldmaster (1954). Even so, the Freeline with the D650H at its later (150 hp) setting would outrun a Worldmaster in city service. Perhaps surprisingly, the Gardner 6HLX engine was never offered on the Freeline, even though it was available from circa 1958, and no doubt had customer appeal.

Daimler's timing for the addition of a long wheelbase, 36 ft export version was about the same as AEC's. Leyland offered this option from the start with the Olympic and Royal Tiger. Guy did not develop a long version of the Arab UF as far as I can trace, but the Victory UF seems to have been optmized for Benelux 11-and 12-metre applications.

The choice of Lockheed constant flow hydraulic brakes was not inconsistent with what was happening elsewhere in the UK commercial vehicle industry at the time, where manufacturers who were previously vacuum brake-orientated saw the hydraulic system as a lighter alternative to air brakes, particularly for the domestic market where quite severe weight restrictions then existed. However, customers resisted the concept as complex and potentially troublesome. Quite wisely, Daimler never offered a vacuum brake option for the Freeline. On the other hand, alone amongst the peer group, the domestic (and short export) version of the Leyland Royal Tiger could be had with vacuum brakes.

Unlike Leyland (Tiger Cub), Guy (Arab LUF) and AEC (Reliance) Daimler did not develop a lightweight version of the Freeline, and this surely inhibited its domestic market prospects. Neither did it update and/or simplify the Freeline chassis. On the other hand, Leyland moved quickly in replacing the Royal Tiger with the Worldmaster in 1964, Guy introduced the Victory UF (with optional advanced features) in 1958, and AEC the Regal VI in 1960.

And again being the odd-man-out, Daimler did not develop a front vertical-engined “trambus” derivative. Guy started this trend with its Victory Trambus derivative of the Victory UF, Leyland followed with the Worldmaster Vertical, although few were built, and AEC segued the Regal VI into the Kudu.

Neither did Daimler offer a manual transmission throughout the Freeline’s life. AEC soon added a 4-speed synchromesh option for the Regal IV; Guy offered 4- and 5-speed constant mesh gearboxes for the Arab UF from the start. Nominally, the Leyland Royal Tiger was available only with a 4-speed synchromesh gearbox, but its successor, the Worldmaster, was available only with the Pneumocyclic. Guy offered synchromesh and constant mesh manual gearboxes on the Victory UF as alternatives to the two-pedal Wilson. And AEC offered a synchromesh option for the Regal VI.

In not offering a 36 ft Freeline chassis tailored the UK 1961 C&U regulations (which would have required a shorter wheelbase than 20’4”, say around 18’6”) Daimler was hardly alone; there were no corresponding Regal VI, Worldmaster or Victory UF variants, either. This market went to the AEC (Reliance 2U and 4MU) and Leyland (Leopard PSU3) medium-weights. Evidently Daimler saw its planned rear-engined design as meeting this requirement, and probably expected it to be available in 1962. In the event, it wasn’t released until about the same time as the AEC Swift, and after the Leyland Panther, effectively minimizing Daimler’s chance of breaking into the market.

So, perhaps due to Daimler’s apparently diffident attitude to development, the Freeline had but modest sales. Leyland was the clear leader in the heavyweight underfloor class with its Royal Tiger and Worldmaster models. AEC did reasonably well with its Regal IV and to a lesser extent with the Regal VI. How well Guy did with the Arab UF and Victory UF is unknown to me. The Arab UF in particular is an obscure model as far as literature references are concerned.

Cheers,

[RK215]

For comparative purposes, the 22 known Australian Freelines are presented below in chassis no order. Looking at them in this manner demonstrates a distinct trend:

456 : 25020 - 02.04.1953 - 5mech - MBB B48F / BO B45FR
457 : 25049 - 05.08.1953 - 5mech - MBB B48F / BO B45FR
166 : 25055 - xx.xx.1953 - 5mech? - Lawton B42F - Gardner 6HLW
455 : 25079 - xx.02.1954 - 5mech - MBB B48F
458 : 25307 - 25.03.1954 - 5mech - MBB B48F
459 : 25406 - 20.01.1955 - 5mech - MBB B48F / HP B45FR
460 : 25408 - 23.03.1955 - 5mech - MBB B48F / HP B45FR
461 : 25409 - 20.05.1955 - 5mech - MBB B48F / HP B45FR

462 : 25570 - 07.09.1956 - 5pneu - MBB B48F / MBB B49F (ex-458)
289 : 25571 - 26.04.1957 - 5pneu - HP B45F
288 : 25572 - 09.04.1957 - 5pneu - HP B45F
293 : 25573 - 02.07.1957 - 5pneu - HP B45F
290 : 25574 - 08.05.1957 - 5pneu - HP B45F
292 : 25575 - 17.06.1957 - 5pneu - HP B45F
291 : 25576 - 23.05.1957 - 5pneu - HP B45F
294 : 25577 - 26.07.1957 - 5pneu - HP B45F
299 : 25578 - 18.10.1957 - 5pneu - HP B45F
298 : 25579 - 24.09.1957 - 5pneu - HP B45F
300 : 25580 - 08.11.1957 - 5pneu - HP B45F
297 : 25581 - 06.09.1957 - 5pneu - HP B45F
301 : 25582 - 27.11.1957 - 5pneu - HP B45F
296 : 25583 - 16.08.1957 - 5pneu - HP B45F
295 : 25584 - 01.08.1957 - 5pneu - HP B45F
305 : 25585 - 28.03.1958 - 5pneu - HP B45F
304 : 25586 - 20.02.1958 - 5pneu - HP B45F
302 : 25587 - 02.12.1957 - 5pneu - HP B45F
307 : 25588 - 13.05.1958 - 5pneu - HP B45F
303 : 25589 - 18.12.1957 - 5pneu - HP B45F
306 : 25590 - 30.04.1958 - 5pneu - HP B45F

464 : 25665 - 17.11.1957 - 4pneu - MBB B48F / BO B45FR
465 : 25666 - 08.12.1957 - 4pneu - MBB B48F / HP B45FR
463 : 25690 - 02.07.1958 - 4pneu - MBB B48F / BO B45FR.

Indeed this tabulation presents an interesting picture. Allowing say a year between chassis manufacture and service entry, it is apparent that the very early examples predated the availability of the pneumatic-over-mechnical gearchange. It is open to seculation whether the 1955 examples had mechanical gearshifts by operator choice or simply by availability. If the latter, then the availability of the pneumatic-over-mechanical gearshift must have occurred later than the addition of the air brake option in 1952.

The change to 4-speed for the three late Scarborough examples is curious. Just possibly, they had the air-operated gearbox, not the pneumatic-over-mechnical type. This entered production late 1956, so the timing is just possible.

Quite a few Freeline history datapoints are locked up in the MTT fleet variations.

Cheers,

[Herbert]

RK215, had the chance to talk with an ex-Scarborough Bus Service mechanic yesterday regarding their Freelines. As I have been finding a number of times recently whilst digging throught the Perth fleetlists evidence, the "official" record is somewhat wayward.

Hopefully tomorrow I'll be able to put into some sort of order my notes from that conversation - stand by!

[RK215]

Thanks, Herbert - I look forward to the update.

Regarding Freeline chassis numbers, the following list shows where the Perth examples fit as compared with the large Auckland fleet.

25020 Scarborough

25048 Passenger Transport Co, Auckland (PTC)
25049 Scarborough

25055 Adelaide

25079 Riverton

25081 )
Auckland Transport Board (blah) – 90 total
25170 )

25179 PTC
25180 PTC

25387 PTC
25388 PTC
25389 PTC

25403 PTC
25404 PTC
25405 PTC
25406 Scarborough
24407 (Allegedly exported to Australia)
25408 Scarborough
25409 Scarborough

25434 PTC
25435 PTC
25436 PTC

25472 )
blah (70 total)
25541 }

25570 Scarborough
25571 )
WAGT (20 total)
25590 }

25665 Scarborough
25666 Scarborough

25690 Scarborough


The PTC nine had 5-speed gearboxes, hydraulic brakes (although I don’t know which variety) and power-assisted steering. I think that also had hydraulically-assisted or hydraulically-operated gearchanges, but detailed information is hard to come by.

Interestingly, the 20 Sydney Daimler CVG6 single-deckers were also “hydraulic” buses. In their case, the gearchange was evidently hydraulically assisted, not hydraulically operated. At least, when I visited Tempe Museum back in 2005, I was advised that the gearshift pedal was subject to severe “kickback” if not fully depressed, which indicates that there was a mechanical linkage between the pedal and the gearbox.

Happy New Year!

[Herbert]

RK215, again your additional input is very helpful, and the inclusion of the NZ chassis nos fills out the picture. I am, however, also interested in a comment you made about the NZ ones having different brake & actuator pedals.

Unfortunately my notes of the conversation with the ex-Scarborough mechanic aren't as precise as I had hoped! Perhaps I should have recorded the conversation. Nevertheless, here's the gist of it:

The change to 4-speed for the three late Scarborough examples is curious. Just possibly, they had the air-operated gearbox, not the pneumatic-over-mechnical type. This entered production late 1956, so the timing is just possible.

He states that the last four Freelines delivered had air actuators & confirmed that that was a full air system with a slave unit at the gearbox end. The chassis concerned are:

25570 Scarborough 38/MTT 462 - new 09/56
25665 Scarborough 41/MTT 464 - new 11/57
25666 Scarborough 42/MTT 465 - new 12/57
25690 Scarborough 15/MTT 463 - new 07/58

At least two (41 & 42) originally had air-steering, also (my notes not clear enough as to whether this applied to all four of them) - found to be "all or nothing" & therefore dangerous.

This information conflicts with the MTT-derived data which stated that 462 was new with a 5-speed air-actuated box - but I am convinced about the reliability of my new source. What better could you get than information from a mechanic who actually worked on them and knew the entire fleet intimately?

Is it possible, considering the significantly different (original) bodies on 41, 42 & 15 (463-464), that 462 was erroneously recorded by an MTT clerk as being more like the other units (456-461) which shared the same body style?

If the 4-speed air-actuated box was only offered from 1956, then the disputed bus, 462, might have been one of the earliest examples.

Scarborough also had 3 CD650s with full hydraulic systems, with another in the Carlisle fleet:

17772 Scarborough 28/MTT 72 - new 12/51
17773 Scarborough 29/MTT 74 - new 03/52
17774 Carlisle 8 / MTT 71 - recorded as being new in --/51, but considering it was SBS 29's twin, more likely to be --/52
17987 Scarborough 30/MTT 75 - new 12/52

Their gear selectors were located on the left of the steering column. If I recall the conversation correctly, the hydraulic systems on the Scarborough examples were progressively reduced to just the braking system. Certainly the power-assisted steering was disabled early on.

Not sure about the Carlisle unit, or what modifications the MTT later did - but one would expect that, like all other areas of it operation, there would have been a drive towards standardisation, hence, getting back to Freelines, why all of them (except the early withdrawal, 458) are reported as having been converted to 5sp pnuematic during 1962.

Having said that, it would be interesting to compare an ex-Scarborough unit (if only one could be found) with dilligaf's to once again test the written record. However, the selector & pedal set-up in 299 was in complete accordance with my memory of the single ex-Scarborough unit I've travelled in, with the actuation method appearing to be identical.

Another historical note not previously recorded: it has been suggested that the government had insufficient funds to take over Scarborough Bus Service at an earlier date. When they finally did so in April 1962, they did not purchase the large supply of Freeline spares - but within nine months withdrew one Freeline, 458, cannabilising it for parts and transferring its body to another (462, again!). Later on during the 1970s, several Freelines were similarly cannibalised to keep the others going. How short-sighted that 1962 decision was!

[RK215]

Herbert, thanks much for that additional information.

It adds quite a bit more to the Freeline history, but as you say, raises some more questions, as well. Such is often the way with research.....

Daimler seems to have not had much luck with its power assisted steering systems - either that or it didn't learn much along the way. The air pressure systems were never that common, but from what I can gather could work well enough if designed properly. Early versions evidently had prodigious air consumption, but that problem was solved. I've seen something to the effect that AEC offered air-assisted steering on late Regal IV chassis, as well as the hydraulic type. Some German and Italian builders used it on trolleybuses, as it got around the perennial problem with hydraulic systems - do you drive the pump from a line-voltage auxiliary motor or from the traction motor, each bringing its own difficulties.

Cheers

[Herbert]

... AEC offered air-assisted steering on late Regal IV chassis ...

I've been saving up this bit of trivia for the right moment & it's finally arrived! An MTT Regal VI, 626, trialled air-assisted power steering, but surprisingly late in the peace, ie from September 1979. It was removed by January 1980 due to unpopularity with drivers.

[RK215]

That’s interesting, considering that the Regal VI was offered with optional hydraulically operated power-assisted steering from the start.

Perhaps an air pressure “bolt-on” unit was seen as being easier to fit and/or lower cost than retrofitting the hydraulic system. At least it would avoid the need for fitting a hydraulic pump. I have the impression that in general, aftermarket “add-on” power steering systems are not all that marvellous.

On the other hand, somewhere in a 1960 Bus & Coach magazine, I have seen a comment to the effect that the air-pressure assisted steering on the Regal IV was better, in terms of directional stability, than the hydraulic system on the Regal VI. (Although according to the AEC brochure, the late Regal IV was also offered with hydraulically assisted steering.) This seems to confirm that the “devil is in the detail”.

Returning to the Daimler saga, I have tried to impute some logic into what Daimler did during the late 1940s and 1950s.

The CD650 was somewhat short of Daimler’s vision for a “hydraulic” bus, but represented what was attainable at the time. The constant-flow hydraulic system was new to automotive applications, and because of that, it is understandable that for the primary braking system, power-assistance rather than power operation was preferred. At least that provided some backup in the event of pump failure of loss of power circuit fluid, in that the brake pedal was connected directly to the master cylinder. On similar grounds, power assistance for the mechanically operated gearshift would have been preferred. In the case of the steering and handbrake, power assistance rather than fully-powered operation was mandatory anyway. The handbrake had to be able to hold the vehicle by mechanical means only. Although fully-powered steering is commonplace on on-highway vehicles and construction equipment, it is almost unknown on on-highway vehicles. (Unless one counts vehicles such as street-legal ADTs and those Aveling-Austin 4x4, 4-wheel steering graders.)

A little later, with some service history, Lockheed and Daimler graduated to the fully-powered “Powervalve” braking system, and, at the same time I would surmise, fully-powered operation of the gearshift, with an external hydraulic cylinder connected to the gearbox busbar operating lever. Logically, if fully powered operation was by then deemed acceptable for the braking system, it was also acceptable for the gearshift, and its use would allow some simplification of the layout. Daimler’s decision to retain the spring-operated preslector gearbox and simply apply an external hydraulic unit can be seen as rational in context. Firstly, it meant that the standard 4- and 5-speed gearboxes could be used. Although I think that SCG had a preselector design that used an internal hydraulic operating cylinder, this would not have fitted the Daimler concept of a central hydraulic system. It would have had its own internal pump, and probably would have required electric (or other remote) control of an internal hydraulic valve,

So far, so good, but some customers wanted air brakes. So Daimler modified the Freeline accordingly, circa 1952 as best as I can discern from the available sources. Something I do not know is whether the air-assisted steering and air-operated gearshift options were developed at the same time that air brakes were offered, or added later on. In the case of the gearshift, Daimler apparently simply replaced the hydraulic servo with an air pressure servo. Again, this was justifiable on the basis that the standard 4- and 5-speed gearboxes could be used, although in this case, Daimler did have the option of using the internally air-operated gearbox, as pioneered by AEC and also used by Guy. Perhaps by then its projection for Freeline sales would not support a business case for manufacturing two additional gearbox variants. At that time, its vertical-engined models, except for the CD650 which was by then being phased out anyway, had vacuum brakes and mechanically-operated preselector gearboxes. These, particularly domestic market double-deckers, would have constituted the majority of its production.

So again, so far, so good. But in 1956, we come to a twist in the road, with the introduction of 30 ft long double-deckers in the UK. Daimler undertook a fairly significant redesign with its CVD6-30 and CVG6-30 models. In fact, it more-or-less had to; whereas AEC, Guy and Leyland could easily interpolate, as it were, between their respective 27 ft double-decker chassis and their long-wheelbase export single-deckers, Daimler didn’t have that option. For the CVD/G-6-30, Daimler specified air brakes and an air-operated 4-speed preselector gearbox. But instead of using the existing gearbox with an external air pressure servo unit, it followed the AEC pathway and introduced an internally air-operated gearbox. One can only suppose that the expected sales were seen as justifying the development of a “new” gearbox, which in turn was seen as being an improvement over the spring-type. But even accepting that, what was a little odd was that this happened in mid-1956, by which time AEC and Leyland were well-established with their respective Monocontrol and Pneumocyclic gearboxes. Perhaps Daimler saw its customers as being very traditional, and not wanting to have anything to do with “two-pedal” buses.

I have never seen any evidence to suggest that the 5-speed preselector gearbox was ever offered in internally air-operated form. There is no obvious reason why the 4-speed internally air-operated version would not have been fitted to the Freeline if requested, but whether that actually happened is uncertain.

Notwithstanding Daimler’s mid-1956 recommitment to the preselector concept, at the end of 1957 it did introduce its Daimatic semi-automatic gearbox, its counterpart to the Monocontrol/Pneumocyclic. Initially it was available only as a 4-speed model. Pre-British Leyland, I think that there might have been a 5-speed version fitted to some Roadliners, but this could well have been a Guy-built unit. The Daimatic was offered on the Freeline as well as on the vertical-engined models. Nevertheless, the preselector gearboxes remained available on selected models until the late 1960s.

The foregoing is nothing but a post facto rationalization, but it does point to the following gearbox timeline:

1948 – Daimler introduces hydraulically assisted mechanical preselector gearbox operation on the CD650, applicable to both 4-speed and 5-speed variants. The same facility is later available on the early Freeline, and was applied to other exports (at least the Sydney CVG6 fleet.)

c.1952 – Daimler introduces externally hydraulic operation for its preselector gearboxes, applicable to 4- and 5-speed variants, and used at least on some export Freelines.

Sometime between 1952 and 1956 – Daimler introduces external air operation for its preslector gearboxes, applicable to 4- and 5-speed variants, and used at least on some export Freelines.

1956 – Daimler introduces a new, internally air-operated 4-speed preslector gearbox for its new CVD/G6-30 model, but also applied to other models. Unknown if it was fitted to any Freelines.

End-1957 – Daimler introduces its Daimatic 4-speed semi-automatic gearbox, largely supplementary to, rather than as a replacement for its preslector gearboxes.


Cheers,

[RK215]

Some preliminary information that has come my way recently adds a bit more – with a twist - to the picture concerning Daimler’s brake and gearchange activities during the 1950s.

The export CD650 single-deck chassis was offered with optional air pressure equipment quite early on. This consisted of full air brakes, evidently with piston-type actuators, and an air-assisted handbrake. The preselector gearchange was also air-operated or air-assisted, it not being readily apparent which of the two forms was used. Neither is it apparent that air-assisted steering was offered on this model.

Sometime I acquired a brochure describing the original CD650 hydraulic system, which operated servo-type brakes, the power-assisted steering, and the power-assisted gearchange and handbrake. The braking system is interesting, in that the rear wheel brakes were operated from their own master cylinder that in turn was driven by the pressure hydraulic servo and the brake pedal, making it a power assisted system with direct pedal operation backup in the event of pressure loss. However, the front wheel brakes were powered directly from the pressure system via the servo reaction valve, making this part a fully-powered system. The handbrake and gearchange had identical hydraulic servo units that acted on the respective linkages. Thus the gearchange pedal would have been subject to the same “kickback” action as could happen with mechanically operated preselector gearboxes. But even with loss of hydraulic pressure, gearchanging was still possible.

The Freeline was also offered with optional air pressure equipment reasonably early on. In this case there is no mention of an air-assisted handbrake option, but air-assisted steering was optional. The brakes were of the full air type. The preselector gearchange was of the air-operated type, evidently with an external diaphragm unit, with air pressure required for disengagement, that is the opposite of the situation with the AEC air-operated gearbox. This is fully consistent with the evidence previously presented here and on other threads. An apparent disadvantage of this system is that loss of air pressure could mean that the bus becomes disabled but “stuck in gear”. But here is the surprise. At or about the same time as the air pressure option was first offered, Daimler also offered a two-pedal option with Leyland-style pedestal-type direct air operation. The conventional wisdom is that Daimler did not adopt the internally air-operated, direct selection version of the SCG gearbox until later 1957, when it was released under the “Daimatic” name, with CAV-type electric gear selection, as used by AEC. The Daimatic gearbox was manufactured by Daimler itself, under license from SCG. And later Freeline literature refers to the Daimatic option, picturing the CAV-type gear selector. Possibly, then, in order to remain competitive, Daimler was prepared to buy-in gearboxes made by SCG itself or Leyland, and pedestals from Leyland. As far as I know the pedestal was developed by Leyland itself, not by SCG, so would not have been available directly from the latter. This could have happened from about 1953 onwards, and presumably was offered until the Daimatic started production. Whether any pedestal-fitted Freelines were built is unknown; it may well have turned out to be a paper option.

Anyway, I’ll comment further once I am able to see the follow-up to the preliminary information.

Cheers,

[Herbert]

Another great instalment from the guru! Thanks!

From memory, leyland4ever converted his Freeline to "monocontrol".

[Dennis96]

And to end this thread, 299 (a goer) may become a static beach shack for a fisherman north of Perth. BPSWA considers 299 a most valuable exhibit and would have paid the price - combination of society funds and several members donating to get the bus. Nevertheless, we will perervere and hope we can obtain it. And I'm told its fleet mate 295 that survives in a caravan park on Welshpool Road has had such an extensive caravan conversion that its price would be beyond the reach of the enthusiast movement - a pity because the caravan component is worthless to us - in fact its a detriment as its only something we would have to rip out to get the vehicle back to bus configuration.

[leyland4ever]

[quote]From memory, leyland4ever converted his Freeline to "monocontrol".


No - it had already been converted to a 4-speed monocontrol (from 5 speed, mechanical actuation pres-select) by the former owners, Bridglands Passenger Transport (who operated the Dover Gardens route in Adelaide).

It was built with a single front and double centre doors (somewhere in all this, I saw a reference to it being B42F), but Bridglands removed the centre door quite soon after they purchased it from the MTT in 1957. Incidentally, unique for the MTT, as far as I am aware, the doors were operated electrically (no air at all!) - each door had a master switch to switch the door 'on', and then there was a push button above the switch to open the door, and another below the switch to close it.

There was also a query (which I can't find now) quite early in the thread about the Adelaide three-doors.

In case it was not answered, the '600' series AEC Regal Mark 1Vs, 600-670, had a pre-select gearbox (full air operation), while the 700 series (701-770) had monocontrol.

The Leyland Worldmasters (800-190 & 901-978) had full pneumatic gear operation.

Cheers

Trevor

[Fleabag]

I hope something can be worked out here.

[marc506]

Is there any reason why the pictures aren't visible?

[Dave Wilson]

Don't worry, its not the first time that enthusiasts have been played off against caravanners etc. in the purchase of a bus. Could you propose a swap and a cash adjustment to get it?

[Fleabag]

Here is 299 at her new home at Whiteman Park today:

http://graham169.fotopic.net/p49593791.html

[system improver]

Here is a photo of the controls of MTT Adelaide 166. Perhaps someone can explain what we are looking at, in relation to the above discussion.



And one of the bus itself, both from the SROSA with permission

[Herbert]

Fantastic photos. Quite clearly 166 still has its pre-selector. Of note is the different shaped actuator pedal compared to the Perth examples. RK215 would be able to confirm, but I suspect that 166 would match the Auckland examples.

That photo also answers a question I had as to how the dash was originally arranged. The MTT modified theirs with their standard air, oil & water warning lamps.



Was unaware that 166 had a wide centre door.

[RK215]

Fantastic photos. Quite clearly 166 still has its pre-selector. Of note is the different shaped actuator pedal compared to the Perth examples. RK215 would be able to confirm, but I suspect that 166 would match the Auckland examples.

Yes, as I recall, the Auckland Freelines had conventional gearchange and brake pedals, the same as Adelaide 166 appears to have had. The treadle-type pedals appear to have been associated with the "pneumatic" version of the chassis - I'll post a bit more on that when I get a chance.

Cheers,

[Carlisle 8]

17773 Scarborough 29/MTT 74 - new 03/52
17774 Carlisle 8 / MTT 71 - recorded as being new in --/51, but considering it was SBS 29's twin, more likely to be --/52

I have just finished my first reading of this whole very long thread, which I found very interesting.

The above quotation is of a posting 'way back on 05.01.07, but as it relates to my beloved Carlisle 8, I immediately "sprang to attention"! Although I have no record of the actual dates in service of Carlisle 8 and Scarborough 29, I can shed some light on the two buses.

I have known from soon after they were new, that they were basically "twins", as correctly written by Herbert. Carlisle 8 was earlier into service than Scarborough 29. The latter, being Bolton bodied, was unusual in a fleet which usually used bodies built by its own body builder. My 'way back information was that 29 became available for purchase and was bought by Scarborough, a Daimler operator. I never had definitive information as to how it came to be available, but I had the theory that it might have been a speculative production, or "speccie". After I joined this Board, I recall "Guy Arab" writing me a p.m. to the effect that his belief was that 29 had been intended for Carlisle, but that Carlisle could not proceed with the purchase, due to financial stringency. That is an interesting and plausible explanation. It could well be correct, but, of course, it cannot be proven to be correct.

What all of that leads to, is that the buses being new in 51 and 52, is very likely to be correct.

[RK215]

Anyway, I’ll comment further once I am able to see the follow-up to the preliminary information.

That's what I said back in March re information that was then coming my way re the optional air pressure systems on the CD650 and Freeline, so this post is somewhat past due.

The information for the CD650 is contained in a brochure covering the single-deck chassis. I suspect that it was not the original brochure for this model, but a second or subsequent edition released when the air brake option was added. The brochure number is 602/2026/E/AIR; it has six sides, of which four are basically similar to the brochure for the CD650 double-deck chassis, number 602/2026D; the two additional sides cover the alternative air-pressure system. The brochure is undated, but I would put estimate it to be from 1950 or 1951.

The standard hydraulic system offered on the CD650 single-deck chassis was the same as that on the double-deck model. That is, servo accumulator type service brakes with a 3-to-1 boost, servo-assisted mechanical handbrake and servo-assisted mechanical gearchange, the latter two using the same type of auxiliary servo unit. Servo assisted steering, using the integral column unit, powered from the central hydraulic system, was optional.

Now to the optional air system, which covered service brakes, gearchange and handbrake, but not power assisted steering.

The service braking system was conventional, with piston-type actuators at each wheel. This was consistent with British practice of the time, as diaphragm actuators, already common in US practice, did not start appearing in a significant sense until 1952 or so. (The Leyland Tiger Cub was an early example.)

The preselector gearbox had an air-operated shift with a piston-type actuator mounted to the left hand rear of the gearbox, and controlled by a valve operated by the gearchange pedal, this valve being in a unit assembly with the footbrake valve. The gearchange actuator was pressurized when the gearchange pedal was depressed, i.e. the opposite to the AEC air-operated preselector gearbox case.

Although, as with the hydraulic version of the chassis, Daimler had retained its spring-type preselector gearbox, in the air-pressure case it had opted for power operation rather than power assistance. This seems to have been a departure from its initial “power assisted” policy with the CD650. One may speculate that Daimler was comfortable enough with air system reliability that that mechanical reversion was not seen as a necessity. Or perhaps a suitable air pressure/mechanical servo unit was just not available at the time. Interestingly, standard on the single-deck model was the 5-speed preselector gearbox, with no mention of the 4-speed option, although it was probably available if anyone wanted it.

The mechanical handbrake linkage included a reaction valve that supplied the main braking system, all four wheels, via a double-check valve. This was a simple but unusual layout, and one that lacked full redundancy, in that downstream of the double-check valve, the system was common to both footbrake and handbrake. Later air-assisted handbrake mechanisms usually had full redundancy. For example, the Leyland system, introduced with the PowerPlus trucks in 1960 and offered as an option on the Worldmaster from 1961 and the PSU3 Leopard from 1964, used a separate diaphragm actuator connected to the handbrake linkage. This became quite common in British practice prior to the general adoption of spring brakes in the later 1960s, other examples of its applications being the BMC FJ and Ford D800 trucks. An alternative system, used by AEC and others from about 1964, included triple-diaphragm rear brake actuators, allowing independent pressurization from the footbrake and handbrake.

That Daimler did the handbrake this way does, along with the gearbox case, tend to confirm that a suitable air pressure mechanical servo unit was not readily available. (This is a puzzling question that needs elaboration outside of the scope of this thread.)

In the case of the Freeline, Daimler issued a separate four-side brochure describing the optional air-pressure system. The copy that I have is undated, although allegedly it is from 1956. For reasons to be explained, I don’t think that it is earlier than the beginning of 1954, nor later than the beginning of 1958. Writers such as Alan Townsin record the Freeline air brake option as dating from 1952. So the Freeline air-pressure system brochure that I have is unlikely to be the first edition.

The air-pressure system on the Freeline provided for operation of the service brakes, the gearchange, and optionally the power-assisted steering. However, as on the original Freeline, the handbrake was mechanically operated without power assistance. Unlike the CD650, the braking system used diaphragm actuators, consistent with the trend in British practice then emerging. The air-operated preselector gearbox, either 4-speed or 5-speed, also used an external diaphragm actuator; otherwise the arrangement was essentially the same as with the CD650, requiring air pressure for gear disengagement. Treadle-type pedals were used for both brake and gearchange.

The surprise was that at this time, Daimler offered an optional semi-automatic transmission on the air-pressure version of the Freeline. This is particularly so considering that the Daimatic semi-automatic transmission, offered from late 1957, was billed as “new”. The semi-automatic Freeline is pictured as having a Leyland-style air-shift pedestal. My guess is that Daimler felt that it needed to offer a semi-automatic option in order to be competitive with Leyland and AEC, but did not want to build the gearbox itself, so planned to source the pedestal from Leyland, with the gearbox coming from either Leyland or SCG. The ratio set (1, 1.59, 2.43, 4.28, reverse 5.97) was the same as then used by Leyland for the Pneumocyclic, differing from that applicable to the Daimler’s own 4-speed preselector gearbox (1, 1.56, 2.36, 4.15, reverse 6.10). It seems unlikely that any such Freelines were built, however. If so, surely they would have been mentioned in the literature. Other builders using the Leyland pedestal would have been worthy of comment - I have heard that Atkinson used the pedestal on some versions of its Alpha underfloor chassis.

Given that Leyland announced the Pneumocyclic gearbox late in 1953, it was likely early 1954 before Daimler would have made arrangements to offer it as an option on the Freeline, which is why I think that the above-mentioned brochure is unlikely to be earlier than 1956.

Anyway, at this stage, it seems that Daimler was determined to limit its own epicyclic gearbox production to 4- and 5-speed spring operated preselector types. Power-assisted and fully-powered operation was catered for by external devices, which in estimated chronological order were hydraulically assisted mechanical operation, air-pressure fully powered operation with piston type actuator, hydraulic fully powered operation, and air-pressure fully powered operation with diaphragm type actuator. For customers who insisted on semi-automatic gearboxes, Daimler was prepared to buy-in the necessary components.

This changed in 1956 with the advent of the CVD/G6-30 double-deck chassis, mostly for the UK domestic market. This was fitted as standard with an internally air-operated 4-speed preselector gearbox, very similar to the type that AEC was by then abandoning. Why Daimler invested in an updated preselector gearbox design at this time is hard to fathom, particularly as by then the AEC Monocontrol and Leyland Pneumocyclic has set a new standard. Possibly there was a cadre of Daimler customers who were firmly committed to the preselector gearbox, and expected it to be offered by Daimler; perhaps also Daimler itself was reluctant to abandon what had been an iconic feature for many years. And the extent of retooling required for the internally air-operated gearbox, as compared with the spring-operated type may have been less than with a change to the semi-automatic type. Even so, one may ask why Daimler didn’t simply offer the externally air-operated preselector gearbox as already developed for the CD650 and Freeline. Perhaps some potential operators were concerned that the “pressure-to-disengage” operation mode allowed the risk of a “stuck-in-gear” failure in the event of air pressure loss. I don’t have any evidence that Daimler offered the internally air operated preselector gearbox on other models such as the Freeline; the spring-operated type remained in production until the late 1960s.

Notwithstanding Daimler’s somewhat Quixotic 1956 decision to update its preselector gearbox, by late 1957 it had more-or-less capitulated and introduced its own-produced 4-speed semiautomatic gearbox with electric shift, branded “Daimatic”. This became an option to, but not a replacement for the preselector on all air-braked models, and was the only type available on the later rear-engined Fleetline and Roadliner models. During the 1960s, but before the formation of British Leyland, a 5-speed Daimatic was offered on the Roadliner. I suspect that this was of Guy origin, as when Guy introduced semi-automatic gearbox manufacture, from the start it built 5-speed overdrive and 5-speed deep first models as well as the 4-speed type.

Cheers,