Felix Schmid
In Issue 211 (Nov-Dec 2024), Rail Engineer described the development of the Coventry Very Light Rail (CVLR) project and reported that it was soon to be demonstrated in the city’s streets. Having ridden on the CVLR we are now pleased to report on these demonstration runs which took place between 28 May and 18 June and which carried a total of 3,000 people.
For the demonstration a 220-metre section of the novel shallow (30cm deep) track-form developed by Warwick Manufacturing Group (WMG) has been installed in Greyfriars Road and Queen Victoria Road. It consists of two straight sections, with a mini s-curve, and a 15-metre-radius curve in between, allowing testing of the main features of the vehicle. WMG is closely affiliated with the University of Coventry and has been involved in the project from the start.
Beyond expectations
As part of the development of this track, in April 2023 a 36-metre length of track was installed at the Council’s Whitley Depot facility to measure its performance under extreme conditions. Vibration sensors were fitted along this track and the vehicles passing over it were weighed. This data was fed into a ‘digital twin’ computer model to evaluate the track’s performance over time. After over a million gross vehicle tonnes had passed over this track, it was performing beyond expectations.
The track section incorporates a state-of-the-art structural health monitoring system. This includes strain gauges embedded within the Ultra High-Performance Concrete (UHPC) slabs and in the asphalt layer, as well as accelerometers, pressure sensors, relative movement sensors, and camera systems.
This early production quality installation enables the engineers and operators to study the behaviour of the infrastructure under normal urban service conditions, subject to the CVLR vehicle loads and the impact of mixed road traffic, over the short and long term. The data will feed into a digital twin of the system, allowing predictive modelling, condition-based maintenance and a full lifecycle assessment, as well as future specification refinement.
It is essential that this information is gathered because longevity is a major requirement: the CVLR infrastructure is designed for a 30-year life, with very low maintenance cost. Providing the same service with electric buses would require at least three full rebuilds of the road over the same period.
First impressions
In June, Coventry City Council had invited the public to try out the prototype vehicle on the newly built track section which was laid in just eight weeks. My first impressions were good: a well-integrated standard tramway track, built to an exacting standard, and an elegant low-floor battery-electric vehicle.
Two rides – a total distance of 800 metres or thereabouts – were comfortable, with only a small amount of rolling noise, this despite the use of resilient wheels. The bogies are of a novel and low height design. The wheels are allowed to rotate more-or-less independently thanks to a limited slip differential in each wheelset, to cope with the tight curves expected in urban areas. The load as well as the traction and braking forces are transmitted by means of a bearing designed as a large slewing ring.
There is no primary suspension, but the air suspension integrated in the bogie is used to adapt the floor height to kerb / platform height. The traction motors and track brakes are also incorporated in the bogie. During running-in of the system, top of rail lubrication is being applied manually, and is doing its job.
The VLR vehicle has been built by NP Aerospace, a local defence company. It is an 11-metre-long bogie vehicle with four doors and two driving positions. The capacity is 56 passengers, of which 20 are seated.
The ‘cabs’ are a short-term feature, given that the intention is for the operation to be driverless – that is, autonomous. Once the ‘cabs’ are removed, the capacity will increase by some 8-10 spaces. Automatic operation will allow the system to be demand responsive in a similar way to the metro networks in Lille and Toulouse.
Specifications
Some of the technical characteristics are: 450mm wheel size, 1-metre wheel-base, and 7.6 metres between bogie centres. The overall width is 2.637 metres. The tare mass is 11 tonnes, about 1 tonne per metre, thanks to the use of composites in the construction. A total of 50kWh of electrical energy is stored in two safe and long-life 650V Lithium Titanite batteries. These weigh a total of about 900kg, including the battery control system. These are fast charge batteries, able to deliver 160A to four axial flux machines with a nominal power of 64kW. It has an 80kWh Lithium Titanium Oxide battery, which is the same type as those used on the Class 93 locomotives.
In 2022, the West Midlands City Region was awarded a £1 billion West Midlands City Region Sustainable Transport Settlement which included £71.5 million to develop the Coventry VLR. However, as this is a development project, this VLR money is only released following the successful completion of each development stage. In June, the Department for Transport (DfT) had released a further £12 million of funding. This will enable an 800-metre section from the railway station to the University Technology Park on Puma Way. It is expected that construction of this longer section will commence in 2026 and that this first Coventry VLR route will be operational in 2027.
NOTE: In July, it was announced that the Black Country Innovative Manufacturing Organisation (BCIMO), which owns the VLR test track at Dudley, has gone into administration due to rising costs and a lack of anticipated funding. Administrators are exploring options to sell the facility with a view to keep it as a test facility. Coventry City Council has stated that this will not have any impact on the development of the Coventry VLR system.
Image credit: Felix Schmid