The Anonymous Widower

New Trains For The Docklands Light Railway And The Tyne And Wear Metro

Transport for London and Nexus (The Tyne And Wear Passenger Transport Executive) are both asking for bids for new trains on the Docklands Light Railway and the Tyne and Wear Metro respectively.

Both systems are standard gauge light railways, but how do they compare to each other and to other trains running or soon to run in the UK?

Width and Height Of Cars

This table shows the width and height of various trains, that are currently in use on the UK network.

Note.

  1. What surprised me was how similar the width and height of these vehicles are.
  2. The Class 345 train uses clever design to make the train as wide as possible inside.

Wikipedia says this about how Bombardier Electrostars were designed and built.

The Clubman/Turbostar/Electrostar platform is a modular design, which share the same basic design, bodyshell and core structure, and is optimised for speedy manufacture and easy maintenance. It consists of an underframe, which is created by seam-welding a number of aluminium alloy extrusions, upon which bodyside panels are mounted followed by a single piece roof, again made from extruded sections. The car ends (cabs) are made from glass-reinforced plastic and steel, and are huck-bolted onto the main car bodies. Underframe components are collected in ‘rafts’, which are bolted into slots on the underframe extrusion. The mostly aluminium alloy body gives light weight to help acceleration and energy efficiency.

From what I’ve seen in the media about the manufacture of Bombardier’s new Aventra, the manufacturing methods are similar but improved.

I would suspect that most modern trains are made in a similar way, with extensive use of lightweight aluminium extrusions for sides and roof.

Bombardier’s method of making the cabs of glass-reinforced plastic and steel, must also give the flexibility required to create an appropriate cab for different classes of trains. Currently, there are Aventras on other, that feature  cabs without and with a gangway.

I suspect that Bombardier’s design team for the Aventra made sure that the design of the body could be adapted to produce a replacement train for the Tyne and Wear Metro or the Docklands Light Railway. After all, they built most of the current cars for the DLR!

This all leads me to the conclusion, that production of the bodies for the new vehicles for both routes will not be a problem. And not just for Bombardier! Stadler seem to have downsized a Flirt for Merseyrail.

Using an existing design, must also mean that equipment like seats, air-conditioning, doors and other fitments, just have to resized if needed.

Design Of The Cars

Bombardier have shown with the Aventra, that they can make cars in different lengths for different versions of the train. The Class 710 trains for the London Overground are being built as twenty metre long trains, whereas other variants have longer cars.

All Aventras ordered so far, appear to be walk-through between articulated cars.

The picture shows the inside of one of Crossrail’s Class 345 trains.

So what can we ascertain about the design the new fleets for the Docklands Light Railway and the Tyne and Wear Metro?

Docklands Light Railway

Under Future Stock in the Wikipedia entry for the Docklands Light Railway Rolling Stock, this is said.

TfL is seeking to order 43, 87-metre-long (285 ft) trains, 33 of which will replace the 70 B90/92 trains currently in use, which are the oldest on the DLR. The remaining 10 would support capacity increases in the Royal Docks area. DLR services presently operate with two or three trains coupled together, but the new fleet will be fixed formation units with walk-through carriages equivalent to the length of three current trains. The aim is to issue an invitation to tender for the new fleet later this year, with contract award planned for summer 2018.

Note.

  1. The trains will be walk-through.
  2. The new train length quoted of 87 metres,  doesn’t fit the length of three current trains, but it is close to the length of three current cars, so I suspect that is what is meant.
  3. In the early 2010s, the whole Docklands Light Railway was upgraded for three-car trains.
  4. The trains need the ability to handle tight curves.

It does appear that Bombardier and the other manufacturers  could design a train for the Docklands Light Railway by adapting their current design.

Consider.

  • To handle the tight curves, it would probably be a walk-through train with several articulated sections.
  • The current trains running as a three-car unit are 84 metres long.
  • Each of the current cars is 28 metres long.
  • Each of the current cars is articulated in the middle. Thus a three-car train has six sections.
  • The current cars have four double doors on either side. Thus a three-car train has twelve doors.
  • The new trains will be 87 metres long.

It should be noted that Edinburgh has a similar problem of tight curves and gradients like the Docklands Light Railway. The city’s Urbos 3 trams are just forty metres long, but have seven articulated sections, with six doors on either side.

Note the short sections, which show what is possible in an articulated rail vehicle.

I suspect the following.

  • As the current trains have six sections, this would be a starting point for a new design.
  • Four or five sections would be a more affordable design.
  • There will be an optimum number of sections to handle the curves and gradients.
  • Does an articulated walk-through design need quite as many doors as current trains?

It looks like a good cost-effective design is possible.

Tyne And Wear Metro

Under Proposed New Fleet in the Wikipedia entry for Tyne and Wear Metro Rolling Stock this is said.

In November 2017, the Chancellor Philip Hammond announced that the government would provide £337 million towards the new fleet. The proposed new fleet would consist of 84 trains to replace the existing 90 train fleet, as Nexus believe that the improved reliability of the newer trains would allow them to operate the same service levels with fewer trains. These are proposed to have longitudinal seating instead of the 2+2 bench seating arrangement of the present fleet, and a full width drivers cab instead of the small driving booth of the existing trains. The proposed new fleet is planned to have dual voltage capability, able to operate on the Metro’s existing 1.5 kV DC electrification system and also the 25 kV AC used on the national rail network, to allow greater flexibility. Battery technology is also being considered.

Note.

  1. A dual-voltage capability will be required.
  2. Battery capability would be ideal for short movements and regenerative braking.
  3. In my view longitudinal seating needs a walk-though capability.
  4. Currently, trains are two-car units and generally work in pairs.
  5. Trains can work in formations of three and four units, but the ability is not used.

If trains generally work in pairs would it be more affordable to have four-car trains?

  • Could they be adapted from proven lightweight main line rolling stock, by perhaps giving the trains a smaller cross-section?
  • They would only have two instead of four cabs.
  • They could be articulated, walk-through trains.
  • Class 399 tram-trains have shown dual voltage through one pantograph is possible.

Using a certified main line train, that had been made smaller would surely mean that certification would be easier.

I believe, that a section of the Tyne and Wear Metro works using tram-train principles under the Karlsruhe model, which allows the current trains to share tracks with other rail services.

So the new trains would make it possible for the Metro to be expanded onto main line railways. If they were electrified using 25 KVAC. Freight lines, which might see a reopened passenger service, could be electrified using the current Metro 1,500 VDC system.

It strikes me thyat by getting the design of the rolling stock right, a lot of possibilities could open up for the Tyne and Wear Metro.

 

 

 

 

 

 

 

January 28, 2018 - Posted by | Travel | , ,

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