With modern technology a unit capable of carrying 120 people at 60 mph can weigh under twenty five tonnes and use Flywheel technology for drive regenerated with brake energy harvesting and recycling, only needing a 3.5 car engine for generation of electricity for the on-board instrumentation, lights etc., plus initial spin up of the flywheel storage device. But in Network Rail reality needing two in case of failure, so that a train is not left stranded, blocking the line. You may have noticed that heritage trains running on Network Rail these days have and engine front and rear to meet these rules or a steam engine with diesel behind.


These engines can actually be tuned to run on various eco-friendly products like Propane, Bio Methane, electrical pick up at stations or even in theory Hydrogen. As yet no one having put up the money for research and development, which we see as strange because this would create a totally emission free railway and would push the cost of Hydrogen down. At the moment it is as expensive as petrol due to the cost of bottling it and lack of commercial outlets. But with any power source these are a very efficient vehicle for lines with a lot of stops in quick succession such as trams, metros, urban railways and branch lines.


The only example on Network Rail to date is the early one engined model running the .8 of a mile branch line from Stourbridge Junction to Stourbridge Town. Infact the shortest network passenger rail service in the world


As there is now the technology to make these flywheels in a vacuum allowing them to spin up to 4000 rpm as it was the wind resistance that previously limited maximum revolutions to 2000 rpm. Thus this actually gives around 4 times the storage capacity. The infrastructure investment would also be considerably more cost efficient than for a heavy rail system. As trains are considerably lighter, rails can be lighter and bridges do not need to be as strong due to them carrying far less weight.


If you have ever visited the Tanfield Railway you may have noticed the rails are actually a lot smaller in cross section, and we are told that the cost is, at the time of writing, around £60/m new, rather than £120/m the rails that Network Rail use. Although in practice second hand Network Rail track can be laid much more cheaply if a 25 mph speed limit is not an issue. Add to this the fact that these trains are very quiet. Residents should not go up in arms at the merest mention or re-opening the disused line at the bottom of their garden, or any new system proposal.


Unfortunately the difference in structural integrity (Ability to withstand a crash) between Light and Heavy rail vehicles, being designed with collisions between each other in mind rather than ‘Heavy Rail' means that safety standards do not allow for mixed traffic on the same rails. Except single Lne token working where they are kept apart and our research indicates that there has not been an collision accident under this system since 1874, and even that was due to procedures not being followed.


In theory two trains should never collide, but sadly we all know mistakes do occasionally happen. A collision between a 10 tonne Light Rail train and an 8000 tonne freight train doing 100 mph just does not bear thinking about! So that means the rules are never likely to change, as stronger Light Rail trains mean heavier, and the whole theory disappears in a puff of drag coefficients!


The second of two Class 139 Hybrid Light Rail cars at Stourbridge Junction.


No. 139002 can carry 20-25 seated, 30-35 standing at up to 40 mph. But is limited by track limits to 20mph on what was once British Rails most dangerous pieces of railway.


Brake failure on the 1 in 67 gradient causing many a train to smash into the buffers at Stourbridge Town.




Will Jarman original concept drawing of the new 120 for mixed traffic on Network Rail

There is also a proposal to have an engine and flywheel on each bogie for easy maintenance