Lighter track and lighter trams
One of the objections to constructing a tramway is the enormous capital outlay necessary. The basic reason for this is the weight of the system, both of the trackbed and of the vehicles trundling over it. The answer could be in Very Light Rail (VLR), using lighter track and lighter trams.
I wrote last September of a day conference which I attended with my friend Derrick in South Essex. Subsequently I paid a membership fee to join the Light Rail Transit Association. The first benefit was to receive their monthly magazine, Tramways & Urban Transit. This covers light rail around the globe. The second benefit, impossible during the height of the Covid-19 pandemic, was members’ days out.
The first such day out recently was an invitation to visit the Dudley National VLR Innovation Centre, adjacent to the Black Country and Marches Institute of Technology.
What we might call the ‘back story’ of the VLRIC is the desire of the City of Coventry to introduce a Light Rail system. The brief was to examine recent technologies developed for other forms of transport and apply them to light rail.
“Traditional light rail schemes cost upwards of £25 million per km, in some city centre locations they can cost as much as £100 million per km. This project aims to deliver all of the benefits of trams but at a fraction of the cost – providing a real alternative to the car and helping to improve air quality and reduce congestion.”Coventry City Council
Light rail is not so light
The reason for the great cost is due to the fact that so-called ‘light rail’ is in fact quite heavy. The intention with VLR is to reduce that weight considerably in a number of areas, but essentially the tramway and the rolling stock. The aim is to reduce the weight of rolling stock to less than 1 tonne per metre length.
Because of the weight of traditional tramways, the first expense is redirecting the utilities which lie beneath the road surface. This has to be arranged for a couple of reasons:
- Future access to the utilities. In a traditional system, once the track is laid, it is very expensive, and very difficult, to access the utilities for repair or replacement.
- The weight of track and tramcars would eventually damage the utilities.
So, before you can lay your track, you have to dig up the road and shift your water, gas and sewer pipes out from under. Then you fill your trench with tonnes of concrete before you can lay a single rail.
However, with VLR you can skip these steps. The track is designed not to weigh heavily on the ground, needing only around 300mm (that’s slightly short of a foot, if you aren’t sure) of concrete to support it. As a result access to the utilities is simpler, because you only need to cut out the required amount of track, remove the concrete bed, do your work, replace the concrete and re-weld the rail.
Very light rail equals fewer overheads
Traditional tramways are powered usually from an overhead line delivering about 600V DC. This requires the installation of lineside supports and many kilometres of copper wire. Where felt appropriate, the overhead equipment can be secured to the walls of buildings along the route.
VLR makes use of modern battery technology. Modern batteries, made from lithium and a titanium compound, can hold sufficient charge to give a VL tram up to 40km range. The vehicles can be recharged fully in under five minutes, using a charging point originally designed for recharging electric buses.
As a matter of interest this same battery technology is also being used increasingly on conventional trams, such as the Edgbaston extension of the West Midlands Metro, where there is insufficient clearance under the Fiveways Interchange.
And so to Medway
I came home to Kent with my enthusiasm for a tramway for Medway reenergised. A VLR solution would go a very long way to meeting the objections of the ‘towns’ ’ governors.