By John Doyle

October 2024

Battery powered trains found practical application in the past for instance on the Deeside branch in the late 1950s and in Ireland on the Bray to  Dublin Harcourt Street line, although never widely adopted. With moves to decarbonisation and the future elimination of diesel traction such trains are once again coming to the fore.

London Underground’s D78 trains had a successful career transporting millions of passengers on the District line (and briefly the East London line) for the best part 40 years. The introduction of S stock made them redundant- as Underground trains.

On retirement, many of the trains (built to sub surface loading gauge) were snapped up by Vivarail, led by the late Adrian Shooter, for potential future use on mainlines.

Fast charge conductor rails which provide a top up during 4 minute turnarounds at West Ealing. The rails are fed by lineside batteries

Out of administration Great Western Railway acquired some of Vivarail’s assets and intellectual property rights with a view to progressing the technology for use on branch line services.

Fast charging conductor rails have been installed at West Ealing and a unit has been under test on the Greenford branch for sometime now.

Former D78 stock now 230001 at West Ealing bay platform No.5

While D stock trains experienced many crush loads during their Underground service the prospect of such a load on the Greenford branch is to say the least extremely remote.

Nonetheless as part of practical testing  I recently became one of many human guinea pigs who formed a “crush load”. The objective bing to measure the effects of such loads on the vehicles in practice compared to theory and modelling.

The testing involved joining the train at West Ealing and making several runs over the branch. We were all weighed (anonymously) and organised into groups amounting to approximately one tonne. We them moved from one part of the train to another to order to enable vehicle measurements to be taken.

The West Ealing branch, less than  three miles long provides a safe space for testing taken from “Tracksys”

The experience was quite fun and provided an opportunity to bump into several old friends and colleagues from the engineering fraternity. It also gave an insight into the very real progress being made with battery and fast charging technology.

It is expected the present class 165 diesel unit which works the branch will be replaced by a battery powered train before too long although no dates have been announced.

Human Guinea pigs!