The Anonymous Widower

Raw Material For A New Train

I wrote a couple of days ago about an innovative use of old London Underground trains, to create the D-Train

So what is the raw material; the D78 Stock like? I took a trip on one from Whitechapel to Kew Gardens, where I took the North London Line home.

Scrapyard specials they are not! They ride well on rubber coil suspension, with a quality somewhere just short of the S Stock on the Underground. When the train emptied a bit and I got a seat, it made me wonder, why Transport for London are replacing all of them.

Wikpedia says this about their withdrawal.

The stock is scheduled for replacement by S Stock in 2016. It is being replaced about 15 years short of its intended lifespan, as a consistent fleet will allow for frequencies to be increased.

So that’s why.  It must also be so much easier for staff on the sections of the line, where it shares tracks with the Metropolitan and Circle lines, that all trains are identical and stop in the same place. Passengers also like the walk-through design of the new S Stock, which eases getting on and off. It also increases capacity by spreading it through the train.

I suppose the main problem is their boxy design, which is not by any means sexy! But you could argue, that they look better than a Class 142. They certainly ride better on those rubber springs.

The more I read about this concept the more I like it.

The designers seem to have taken the approach that a good architect would do, when they’re presented with a Listed building like Kings Cross station and told to make it fit for the next few decades. Every preconception has been thrown out of the window and the designers have just concentrated on a limited set of objectives. These certainly include an affordable, reliable train that meets all the regulations and the expectations of staff, train companies and passeners alike.

But nothing of any substance, can be created without good foundations. The current trains ride well, make the maximum use of the loading gauge and thanks to the refurbishment of the last few years, they have an airy feel, with lots of windows that can be opened for ventilation, if required. I suspect too, that say if you wanted to create some new internal components, a lot of the jigs and mock-ups are still sitting in a shed or are on a computer somewhere.

I particularly like the concept of the power pack. Roger Ford in Modern Railways describes it as being so far off the wall, as to be in next door’s garden. Each driving motor car, will have two fully-enclosed power packs or rafts fitted underneath the train, The engine is a Ford Duratorq, which is built in that centre of railway technology; Dagenham. Vivarail claim that one engine will get the train home, but surely the great thing about having four power packs to a train, means that they can be selectively shut down, when the route allows. The Class 185 trains used across the Pennines, have an Eco-Mode, which selectively adjusts the power to the route, so something similar is surely possible. Computers have been used to control multiple engines according to conditions, fuel economy and power need in aircraft for decades, so I suspect the expertise to create a train that chugs efficiently round the country, is not difficult to find. In the ultimate manifestation, the engine control system would be geared to the ERTMS signalling, when that comes in, so the system would start up and shut down engines in an optimal manner according to traffic.

The power rafts give a tremendous advantage for maintenance. Roger says that taking one out will be a simple ten minute job with a pallet truck, and units will be replaced rather than repaired. Obviously, they’ll be repaired centrally. Vivarail says the concept needs less time in depots

The power raft concept also allows a new raft with perhaps energy storage, like a flywheel to be designed and tested. Given the projected life of the trains, I doubt that a Mark Two power will be developed, but who knows?

The design appears to have an amazing degree of flexibility. Look at this page on the Vivarail web site, which shows some example configurations. Trains can have two or four doors per sides, toilets if required and pictures show the classic four-to-a-table-by-the-window layout is possible.

I also think a seaside or country special would be possible with a large area dedicated for bicycles. Sometimes on Ipswich-Cambridge services, there are bikes everywhere and it is virtually impossible to get in and out.

If I look at the concept from my field of project management it is a dream. Trains arrive from London, as they are replaced by new ones, so for a start there is no storage problem. A separate factory produces the power rafts as required, so materials and cash flow are all as needed.

Even testing and certification is not the extended process it must be with a new train.

There are only a couple of problems that have been flagged up.

Some people think the doors are too narrow. But then, the trains currently run on one of the busiest routes in London and cope well.

Roger worries about the reliability of the power rafts and their Ford engines. I don’t, as if they get the control system right and run the engines efficiently, this will make the task less onerous.

I might flag up another – It’s just a pity, that there aren’t a few more D78 trains to save from the scrapyard.


November 29, 2014 - Posted by | Transport | , , ,


  1. […] Raw Material For A New Train, I gave my view and thought they would be a […]

    Pingback by Is The Vivarail D-Train On A Roll? « The Anonymous Widower | September 16, 2015 | Reply

  2. […] For some pictures of the original D78 Stock see Raw Material For A New Train. […]

    Pingback by Battery Class 230 Train Demonstration At Bo’ness And Kinneil Railway « The Anonymous Widower | October 14, 2018 | Reply

  3. […] regularly used the D78 Stock from their introduction in 1980 until their retirement in 2017. In Raw Material For A New Train, I showed a few pictures of one of the last D78 Stock trains to be in […]

    Pingback by A First Ride In A Revenue-Earning Class 230 Train « The Anonymous Widower | April 23, 2019 | Reply

  4. […] Compare it with this picture I took in 2014 and showed with others in Raw Material For A New Train. […]

    Pingback by A Pair Of Class 230 Trains In The Sun « The Anonymous Widower | June 9, 2020 | Reply

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