The LONDON TRANSPORT Volvo Cumulo Citybus: C1

This page created 16th June 2001 by Ian Smith, updated 2nd February 2003.

The Volvo Cumulo Bus: C1

C1 drawing, all-red livery C1 was one of London Transport's one-off experimental buses. It looks rather like a Volvo Ailsa, but was more interesting than that. It was a "London special", a one-off, a Volvo Citybus with underfloor engine with a hydraulic pump/motor and energy accumulator (Volvo Flygmotor Cumulo) connected between the gearbox and differential. While the bus was stopping the accumulator collected kinetic energy, and released it during acceleration, reducing the engine load.

It had an Alexander R body with dual doorway like contemporary Scottish Volvo Ailsas and London Ailsas V1 and V2. In London days it had centre exit doors too. London Transport leased it for three years from August 1985 as part of their Alternative Vehicle Evaluation, numbering it C1. It didn't enter service until July 1986, when it worked on route 102 from Palmers Green (AD). After the trials, in September 1987, it was returned to Volvo.
The Cumulo system was replaced by a standard ZF gearbox before its sale to McMenemy of Ardrossan, a member of the A1 Service consortium. It quickly passed on to Black Prince of Morley. (who have had an interesting collection of ex-LT buses).

Unlike the Ailsas it has remained in service into the new century, and I saw it in Leeds in January 2001, dressed in one of Black Prince's individual but thematic liveries.

C1, Leeds, January 2001 C1, Leeds, January 2001

Photos by Ian Smith: click them for larger versions.

"That's a London registration" I thought, as I pushed a wheelchair down to the City Centre bus-stop in Leeds. I don't remember what happened to the wheelchair, but my camera came out of my pocket in under a second. These are the resulting pictures. Well, what sort of quality do you expect at three o'clock on a dull January Day in the rain in Leeds?


C1   C101 CUL    5/85    demonstrated at UITP Brussels Show in LT livery
                 8/85    leased from Volvo: Volvo Citybus with Cumulo flywheel drive
                 8/85 CS tests, Chiswick experimental
                 7/86 AD into service on 102 (Palmers Green)
                 2/87 AD on 102
                 9/87 AD into store
                         returned to Volvo
                         Cumulo drive replaced by ZF gearbox 
                 */88    bought by McMenemy, Ardrossan (A1 Service)
                 3/89    bought by Black Prince, Morley
                 4/89    in service
                c2/99    with Black Prince
                 1/01    in service with Black Prince
                 8/01    in service 
              by 9/02    sold to Blythswood Motors (Glasgow)  
                10/02    bought by Redline, Penwortham
       12 RED    2/03    reregistered
       C101 CUL  4/05    reregistered
       YIL 6984          rereistered
                 6/07    bought by Lord, Hull

Photographic references

C1  C101 CUL LBH86 p68           new, at Volvo
             ChisWk p67       AD on 105 to White City
             LBM111 p52  2/87 AD on 102 to Chingford Hospital, Golders Green
             AIHLB p96        AD on 102 to Chingford Station, Golders Green
             Bus400p325  4/88    with A1 Service, Ardrossan
             AIHLB p96           with Black Prince in Leeds
             25YBP p40           with Black Prince in Leeds

Ian's Bus Stop C text C history photo refs V text.