London Transport
1949
AEC Regent III RT
Craven H30/26R
After operational trials with the revolutionary new chassis during 1938, initially equipped with a 1932
vintage open staircase ST body, the RT prototype re-appeared in August 1939 with an advanced all metal
body of very graceful appearance built by Chiswick. An order was placed for 150 of the modern double
decker, which was almost immediately raised to 338, with production of 527 each year from 1940 onwards
being intended, though the ultimate envisaged total is not recorded. Then came WW2 and the sudden
curtailment of bus production, though the order for the first 150 was completed. These, however, had
Chiswick built composite bodies, presumably to conserve metal consumption during the hostilities, and
the the last example entered service in 1942. With the end of the war, the RT programme was reactivated
by AEC in 1946, by which time the chassis design had undergone several improvements, notably in the
engine which now had toroidal cavity pistons increasing the maximum output from 100 bhp to 125 bhp,
though LT derated this to 115 bhp in the interests of economy and extended life. The jig built metal
framed bodywork programme for the RT took a while to establish, and the first postwar RT chassis from
1946 went to provincial operators who equipped them with standard contemporary bodies from their own
suppliers. The LT RTs began appearing from 1947 with bodywork by Park Royal and Weymann, but chassis
deliveries began seriously to outpace those of the bodywork manufacturers. In 1948, anxious to update
its tired pre war fleet, LT turned to other bodywork constructors, selecting Saunders-Roe and Craven to
make up the deficit. The Saunders body was metal framed using the firm’s own cruciform pillar design,
but the end result outwardly resembled the standard Park Royal/Weymann product very closely. Indeed, the
Saunders body was held by LT engineers to be of superior constructional quality, and, although Saunders
received a second order for 50, making 300 in total, the unforeseen sharp decline in bus travel from the
early 1950s meant that no others were built. The 120 Craven bodies were very different, being simply
that manufacturer’s standard design married up to the RT cab and bonnet. The bespoke mountings meant
that these bodies were not interchangeable with other RT chassis and this entire batch had to be
overhauled separately at Aldenham. They were delivered between September 1948 and April 1950, the first
twenty seven being painted green for the Country Bus & Coach department, and allocated to Watford and
Windsor depots. The rest were red for Central Bus operation, and their allocation was spread about in
seemingly random fashion. Ironically, from 1949, the supply situation went into reverse. RT chassis
production could not keep up with the increased bodywork deliveries, and London Transport embarked upon
the futile and very costly course of modifying some late STL chassis to accept standard RT bodies. Thus
was born the SRT class which proved to be pitifully under powered with the 7.7 engine and dangerously
under braked. After a service life of about four years they were all withdrawn, the chassis being
scrapped, and the bodies transferred to new RT chassis. As bus patronage declined during the 1950s LT
found itself with a significant fleet surplus of vehicles, large numbers of brand new RT and RTL
deliveries going straight into store. (This, however, did not deter LT from investing heavily in its new
Routemaster for which, at the time, there was no operational necessity.) With large numbers of new RTs
and RTLs waiting to take to the road, the non standard Craven RT fleet was earmarked for early
withdrawal and most went into store during 1955/6, only for twenty red examples to be repainted green
for Country Area service in March/April/May 1956. They did not last long, being withdrawn again between
one and four months later, the expensive repainting exercise being yet another example of LT profligacy.
At merely six to eight years old, the Craven RTs, became bargain purchases on the secondhand market,
going on to serve their new owners for up to a further thirteen years, proof, indeed, that the Craven
body design was entirely sound. RT 1431 was delivered to LT in May 1949 and sold out of stock on 30
April 1956 to the dealer, Bird’s of Stratford upon Avon, being very quickly bought by a member of the
Ardrossan A1 Service, who ran it for ten years. Early in 1966 this bus was secured for preservation, and
the picture shows it at Brighton during the 1970 HCVC Rally. The destination display has been reduced to
represent the situation that prevailed in the early 1950s when linen for bus blinds was in short supply.
Since 2004, RT 1431 has been a member of the Ensignbus fleet.
Photograph and Copy contributed by Roger Cox
06/07/21 - 05:59
I always found the flatter and less rounded sides of the Craven RTs front to
be more attractive than the standard RT body, but the rear was pure Cravens, with its curved upper
deck, lower window and number plate positions.
RT 1 was initially given the Christopher Dodson body of ex-City Leyland
Titan TD111, dating from 1931. It then became ST1140; all very confusing!
Here are two photos of ST1140, which are quite rare
Chris Hebbron
07/07/21 - 05:58
I just like them as buses - but equally like the "standard" RT
design. The Cravens were my favourites of the 100 9612Es delivered to Sheffield Transport between
1947 and 1950. They were among the last in 1949/50. Good looking buses with a long life. Excellent
though they were, the Weymanns had a permanent scowl which detracted from their appearance.
Strangely enough, the lowbridge version (eg RLHs) had a more balanced and appealing appearance - not
a thing said very often of lowbridge buses.
David Paul Oldfield
25/07/21 - 07:18
I believe that fitting the old body onto the new RT1 and disguising it as
ST1140 was with the intention of fooling competitors into thinking that it was just another old
London type.
But as the body came from a TD class, which was filled with various acquired
Leyland TD1s [and some TD2s?], I wonder how much modification was needed to make it fit? The
wheelbase would surely have been different, yet the image above of ST1140 as fitted does not look
out of proportion, or crude in any way. This must have been rather an expensive refit for such a
short time before the modern body was fitted.
Michael Hampton
26/07/21 - 07:09
Good points, Michael. The Leyland TD1/TD2 was the largest class taken over
from the independents by London Transport, not far short of 200. The almost new ones from 1931/33
had modern bodies by Christopher Dodson/Birch Bros. Many of the class finished up with Liverpool
Corporation, painted grey and used for ferrying employees to/from sensitive sites. Incidentally,
I’ve found another, poor, but mystery, photo of ST1140, posing as some sort of mobile unit, with
spats on rear wheels, plus front side lights with reduced lighting area: wartime mode. Yet RT1 was
in service with its new body, pre-war, in mid 1939!!
Chris Hebbron
27/07/21 - 06:37
Several interesting comments here, and thanks, Chris, for those pictures of
AEC/LPTB’s ‘Q ship’, ST1140, surely devised to fool the competition (Leyland) whilst the new
chassis was being tested in service. As Michael has hinted, the disguise of an old open staircase
body from a TD1 might well have been decided by the wheelbase. The early Regents of the ST class had
a wheelbase of 15ft. 6.5 ins, which was slightly curious because Rackham had only just left Leyland
where his new TD1 Titan had been designed with a wheelbase nearly a foot longer at 16ft. 6ins. From
1932 the Regent had a wheelbase of 16ft. 3ins, but none of the later LPTB examples had such elderly
looking bodywork that must surely have been deliberately chosen to camouflage the new beast. The new
RT chassis - certainly not yet known as the Regent III - had a wheelbase of 16ft. 4ins, for which
the old Dodson body must have been adaptable. Chris’s latest picture is a bit of a puzzle because
RT1 was fitted with its new Chiswick built body in April 1939, so what is it up to in that photo?
The threat of war had been hanging over Britain certainly since 1938 when huge production of war
material such as Hurricanes, Spitfires and bombers was initiated, so perhaps ST1140 was used in its
final days as a test bed for wartime specifications.
Roger Cox
27/07/21 - 06:39
Actually, now that all three photos are together, and comparison of the first
two with the bottom one is possible, it is quite clear that the body on bottom photo is quite
different, bearing all the hallmarks of a Tilling/Dodson body from an ex-Tilling ST, some of which
started to be withdrawn in the immediate pre-war period. Although body sag might not have been
apparent on these frail bodies in 1939, there is no trace of it, nevertheless. What’s all this
about???
Chris Hebbron
29/07/21 - 06:25
Thank you Roger for your note on the wheelbase dimensions of the related
chassis here. I can quite see how the two inches difference between a TD1 and the RT prototype would
be quite easily dealt with in LT’s workshop without showing any obvious crudity. No doubt it was
written up as a "research and development" expense, along with everything else that was
involved. I had thought that there would have been a very different wheelbase dimension between a
TD1 and an RT - but my assumptions have been proved wrong! I was surprised by the difference between
the first Regents and the TD1, as they were more or less contemporary in design and production. That
seems even more puzzling, but no doubt it’s another story to be told on another occasion.
Michael Hampton
11/08/21 - 05:45
It’s worth noting that RT1’s new Chiswick body had a seating capacity of
H29/26R suggesting that it would have breeched the gross vehicle weight limit in force at that time
if the standard H39/26R capacity was used.
The gross vehicle weight limit was relaxed during
the war and again after the war.
Michael Elliott
17/08/21 - 06:30
I had not thought of it before, but some years ago it was pointed out to me
that timber/composite rames were heavier than metal. The "Prewar" RT1-150 were of
composite construction, unlike the post war bodies. It is likely that they might be heavier and that
certification require fewer seats.
David Oldfield
18/08/21 - 05:52
You are probably generally right about the weight of timber frames versus
metal frames. But I have a feeling that in the case of the RT family, the "pre-war" ones,
[RT2-151] were actually lighter than the post-war version. I have a memory that some of the pre-war
machines were kept in service for a longer period than most of the batch due to their allocation for
a route over a weight-limited bridge or similar structure. The post-war ones deemed as too heavy. I
cannot now remember what route it was, but think it was the outer London suburbs, north of the
Thames. I assume that the offending structure was rebuilt or the route diverted when the time came
to withdraw these last few pre-war RTs.
Michael Hampton
21/08/21 - 06:15
It was Country Area route 327 that used them.
Ian Mason
22/08/21 - 06:22
Yes, Ian is correct. The Hertford garage based 327 route between Nazeing and
Broxbourne crossed a weak bridge over the railway. This service was one of the last strongholds of
the postwar STL class until they were displaced in May 1955 by seven wartime RTs, with engineering
backup from a couple of others, one in red livery, that served as trainers but still had full psv
certification. The Chiswick composite constructed body of the wartime RT had an unladen weight of 6
tons 15 cwt, significantly less than the 7 tons 10 cwt of the Park Royal or Weymann bodied standard
RT. When the bridge was suitably reinforced, these RTs were withdrawn in August 1957. I acknowledge
Ian’s Bus Stop for padding out my memory with accurate dates.
Roger Cox
22/08/21 - 06:23
There were seven of them, RTs 36, 62, 79, 93, 114, 128 and 137, nicknamed
"The Magnificent Seven!". They were all re-painted into green and based at Hertford Garage
from 1955 to 1957. Some had full blinds, even the route number box, but some had one-piece ex-STL
blinds. All, bar one, lasted until 1963, some finishing as learner vehicles or as Aldenham hacks.
Postwar RTs weighed in at 7.5 tons if memory serves, but the wartime ones were definitely
lighter.
Chris Hebbron
25/08/21 - 05:52
Here’s a photo of Green RT 128, fully blinded, on route 327.
Chris Hebbron
03/10/21 - 17:23
The vehicle shown in Chris Hebbron’s picture of 26 July is not RT1 (aka
ST1140) with its Dodson body. It is an early postwar 3RT chassis, 0961079, new in 1947 which was
used as a training chassis for, I believe, the depot engineers.
Because chassis production at
the time was outstripping body production, it was evidently decided to use a secondhand body, and
the Tilling body from ST977 was fitted. The vehicle was known by its chassis number and never had a
Service Vehicle number.
It lasted in this role until 1953 when the body was scrapped and the
chassis emerged with a new Weymann body in 1954 as RT4761. However it was stored until 1958 and the
chassis was eleven years old when it finally entered passenger service.
Basil Hancock
05/10/21 - 06:12
Thanks, Basil, for clearing up the mystery of my 26th July posting. What an
extraordinary history of the chassis, taking 11 years before it finally appeared in revenue-earning
service as RT4761 And a Tilling ST body fitted here without any sag!!
Chris Hebbron
06/10/21 - 06:19
RM8 took even longer, not entering passenger service until 1976 when it was 18
years old. This made it the last rear entrance and the last half-cab double decker to enter service
in the UK, although it was not exactly new at the time.
And just to add to the statistics,
Chiswick Experimental RT3995 only operated in passenger service for three months before becoming
Chiswick’s new toy. Even Merlins and Fleetlines lasted longer than that.
Here are two photos of the former Chiswick Experimental RT3995 in service with
Spencers in High Wycombe on 3 November 1969.
I am not sure who did the rear end modification,
but it looks quite professional so it might have been LT themselves.
Basil Hancock
07/10/21 - 06:27
Interesting about RM8, Basil. RT3995 looks very well turned-out, but looks a
little odd with that style of enclosed platform. Thx again for letting us know about these sorts of
oddities, otherwise lost over the years.
Chris Hebbron
10/10/21 - 19:27
RT1431 was strutting her stuff between Dorking and Putney Heath on the 93
running day yesterday (9 October) - along with RT1 and sundry other members of the RT and RM class.
RTs predominated and most of the buses were "showroom" condition - a testament to the hard
work and care lavished on them by their owners. I’ve said it before but, Three cheers to the
preservationists who continue to make these events possible.
David Oldfield
11/10/21 - 20:26
Wish I could’ve gone, David. Living at Morden until 1956, the 93 was our
long-distance through-route, initially served exclusively by 1RT1s, but Sutton’s D’s would later put
in an appearance and Merton’s STL’s and D’s would appear on the Summer Sunday extension from Morden
to Dorking, when I’d persuade my mum to splash out for a ride into the country and green buses! In
those days, that whole journey was in Surrey!
Chris Hebbron
