Many regular rail travellers will have experienced that sinking feeling when the train they are waiting for doesn’t arrive. First of all interest, then concern, followed by worry, despair and finally anger.

With the modern passenger information systems at stations these days, at least people know what’s going on. “Points failure at Peterborough”, “Signalling problems at Slough”, “Wiring down at Watford” and, worst of all, “Leaves on the line at Leatherhead”.

All of these are infrastructure failures. Network Rail, as infrastructure owner and as reported many times in The Rail Engineer, is working hard to minimise these problems and the delays they cause. And the train punctuality figures are slowly creeping up as a result.

Failed trains

But some 20% of delays are actually caused by the trains themselves. Often that is simply what it is, a delay, but a completely broken- down train can cause real headaches, not only for the passengers on or waiting for that train, but for all the other trains that get stacked up behind the failed one.

What is needed is a way to get a dead train off the running line as quickly as possible, so that the following services can continue on their way. Also, any passengers on that train have to be taken to a safe place to disembark. The obvious way of doing this is to use another train to drag the failed one out and take it to the next station. However, that’s not as easy as it sounds.

Class 57 Coupler Mods 002 [online]

Modern trains are complex animals. They are designed to work as a unit – even adding extra coaches is a complicated process which has to be carried out in a workshop over several days. That means they aren’t really set up for receiving outside assistance.

For a start, different train manufacturers use different couplers. So, just fastening on to a train can be problematic. Then, in these days of ‘fly by wire’ systems, everything is controlled by train management systems and those are different for every class of train out there.

The easiest way to collect a failed train is therefore to send a sister train out to connect to it. This will have the correct couplers and the correct electronic systems. However, one may not be available. The rescuer will use the same power source (overhead wires, third rail) as the stranded train and, if there has been some damage to that or the power has been switched off, then it will be useless. And finally, having a rescue vehicle that could be 250 feet long may be unhandy in some circumstances.

Thunderbirds have gone

To address these problems, Virgin Trains kept a fleet of rescue locomotives close to the West Coast main line. These Class 57/3 locomotives, known as Thunderbirds with names such as “Scott Tracy” and “Lady Penelope”, were fitted with Dellner retractable couplings and could connect to both Pendolinos (Class 390) and Super Voyagers (Class 221). In addition to rescue duties, they were used to haul Pendolinos along routes without overhead wiring, extending the range of these trainsets. However, as these requirements decreased, the locomotives were returned to leasing company Porterbrook towards the end of 2011.

Network Rail acquired six locos for use hauling its winter de-icing trains, earning them the nickname “Snowbirds” – a reference to their Thunderbird origins. They were also used on test trains.

However, the rescue role was never very far from Network Rail’s mind. Mick Stewart, senior fleet engineer, and his team at NDS (National Delivery Service) worked on a plan to use these locomotives to recover stranded trains, mainly electric multiple units (EMUs) in the south of the country.

The Dellner couplers were retained on four of the locos, although they were lowered by about 100mm as Pendolinos have a particularly high coupling. The other two locomotives were fitted with Tightlock couplings. Planned by Network Rail in conjunction with Porterbrook, the work was carried out by Brush at Loughborough.

Compatible systems

A bigger challenge was to get the locomotives ‘talking’ to the electronic brain of the stranded EMU. Originally built as Class 47s in the 1960s, they were rebuilt as Class 57s at the end of the 1990 with the original Sulzer diesel engines replaced by EMD units. As a result, they are fairly unsophisticated locos with mechanical controls, ideal for accessing areas of the network where electrical power may be out, but not much good at interfacing with a modern, electronic, train management system.

Virgin Thunderbirds DSC_3112 [online]

So the project team (NDS working with Porterbrook and Atkins) concentrated on fitting pressure switches and pickups so that control commands could be sent to the stranded train. Using various adapter cables, the Class 57/3 can now feed 110V power to the EMU and also control both brakes and door opening systems. Compressed air can be fed to the train if its own compressors are offline.

The rescue locos normally deploy from their base at Eastleigh with a crew of two.

All necessary frames and cables are stored in the old boiler compartment. To connect to the stranded train, the driver handles the loco while the crew oversees the coupling up and other connections. These are best done by two people, removing the need for anyone to duck through under the coupling, so the driver of the stranded train is usually drafted to assist under instruction.

Once connected, there are two possibilities. If the train is completely dead, it can be hauled out to a place of safety at low speed. However, if all systems are running and controlled from the 57/3, then the consist can operate at line speed. Although it will probably only run to the closest station, it is actually quite capable of operating the originally intended service.

To test this capability, a four-car Class 377 was hauled from London to Brighton and back last summer, at service speed, with no problems. It ran round at Brighton in 15 minutes, ready for the return leg, with a crew of four (Class 57 driver, Class 377 driver and two fitters).

The fleet can currently rescue the Electrostar family of Class 375, 376 and 377 trains (including Class 357 operated by C2C), the Desiro family (Classes 350, 444, 450), and Classes 317, 319 and 455.

With the ability to couple up to a stranded train and be on the move again within 15 minutes, the speed of recovery has noticeably improved since the new fleet was commissioned. There are plans to stable these useful locomotives around the network, reducing response times still further. Not a bad use for a class of locomotives that is now fifty years old.