Gbrf Class 73’s & Network Rail Coaches

[MistaMatthews]

I often see this train formation at night but can anybody give me some more in depth information about what this train is actually for?

Does each individual coach have a purpose? Do they always stay in the same formations? Any particular routes they travel? Where are they stabled? Why is there a loco on each end instead of a dbso etc?

Many thanks for your help!

 

[Lockwood]

It's a measurement train. I think I've managed to see it once.

AIUI it is a way of checking for track defects over a wider area than doing it with the Mk I eyeball on the ground.


I'm sure someone will be able to give more detail on what it is actually doing

 

[Mollman]

I often see this train formation at night but can anybody give me some more in depth information about what this train is actually for?

Does each individual coach have a purpose? Do they always stay in the same formations? Any particular routes they travel? Where are they stabled? Why is there a loco on each end instead of a dbso etc?

Many thanks for your help!

A good summary here:
https://www.rail-record.co.uk/guide-to-network-rail-test-trains/

I think you will be seeing a PLPR

Plain Line Pattern Recognition uses a variety of tools to measure and detect defects and potential problems that might arise in track condition. PLPR uses equipment such as: 4 foot camera used to check the track condition, thermal imaging to check rail temperature, fasteners are checked with diagonal and top down cameras. The various cameras used store HD laser scanned images which show different angles and planes of the track and rails. PLPR was initially rolled out on the NMT measurement train, but has since been fitted to Network Rail’s coaches and can be seen across the UK rail network. The coaches on the PLPR may also by fitted with Radio Survey equipment, for testing of NRN, CSR and GSM-R communication systems.

DBSOs are used on some 37 powered workings but there aren't many of them and I don't think they are compatible with 73s. I think they might overnight at Tonbridge although Derby is the main base.

 

[Buchholz Relay]

Deleted.

 

[MistaMatthews]

Thank you for your responses. That’s some brilliant information you’ve provided.

@Buchholz Relay can I ask how you got hold of these images? Is this your line of work?

 

[Townsend Hook]

There are four PLPR trains, with varying capabilities. The PLPR1 set generally includes the MENTOR overhead line recording vehicle as well as the PLPR1 vehicle itself. PLPR2 usually includes the ‘Electrification Monitoring Vehicle’ (EMV). PLPR3 is the set most commonly used on the Southern Region, because it’s the only one of the four fitted with the Conductor Rail Inspection System (CRIS), and is the odd one out because it’s track geometry package is in a separate vehicle (999550, the erstwhile High Speed Track Recording Coach) and not in the PLPR vehicle. PLPR4 only has the basic track geometry and PLPR capability common to all four trains. Each set will usually be made up to four carriages with generator vans and brake runners.

The ultrasonic (UTU) trains very occasionally run with class 73s but generally will run with a single 37 and a Mk2 DBSO. Hybrid UTU-PLPR formations also run on rare occasions, but this is generally avoided because while a PLPR set can run at up to 100mph depending on the traction, UTUs are restricted to 60mph transiting and 30mph recording.

 

[MistaMatthews]

There are four PLPR trains, with varying capabilities. The PLPR1 set generally includes the MENTOR overhead line recording vehicle as well as the PLPR1 vehicle itself. PLPR2 usually includes the ‘Electrification Monitoring Vehicle’ (EMV). PLPR3 is the set most commonly used on the Southern Region, because it’s the only one of the four fitted with the Conductor Rail Inspection System (CRIS), and is the odd one out because it’s track geometry package is in a separate vehicle (999550, the erstwhile High Speed Track Recording Coach) and not in the PLPR vehicle. PLPR4 only has the basic track geometry and PLPR capability common to all four trains. Each set will usually be made up to four carriages with generator vans and brake runners.

The ultrasonic (UTU) trains very occasionally run with class 73s but generally will run with a single 37 and a Mk2 DBSO. Hybrid UTU-PLPR formations also run on rare occasions, but this is generally avoided because while a PLPR set can run at up to 100mph depending on the traction, UTUs are restricted to 60mph transiting and 30mph recording.

Again, thank you very much. Some more brilliant information that you’ve posted there! So I think it is PLPR3 according to your descriptions that I’ve seen around. I hope you don’t mind if I could dig a little deeper… What exactly are “brake runners” and “generator vans”?

 

[43096]

Again, thank you very much. Some more brilliant information that you’ve posted there! So I think it is PLPR3 according to your descriptions that I’ve seen around. I hope you don’t mind if I could dig a little deeper… What exactly are “brake runners” and “generator vans”?

Brake runners are additional vehicles included in the formation to improve brake force and allow the train to run at line speed.
Generator vans are just that: vehicles with electricity generators in to provide power for the test vehicles.

 

[Townsend Hook]

The recording vehicles don’t take any electrical power from the locos, onboard generators are used. Sometimes they’re in the recording vehicles themselves, the DBSOs all have generators, and there are a number of 1950s-vintage former luggage vans which are dedicated generator vans.

Brake runners are simply extra carriages in the formation to add brake force. When the trains run at less than four carriages, they’re required to run to lower speed limits because the driver has less braking force available. Some of these are passenger carriages with minimal modifications which have no use beyond acting as brake runners, sometimes spare recording vehicles are used.

 

[BigB]

Similarly, locos coming out of works etc. after overhaul would use a test rake of coaches to allow testing at line speed - there used to be a rake of Serco coaches at Doncaster for this purpose (showing my age...). Light engines are quite speed restricted when running as the brake force is limited.

See this separate topic https://www.railforums.co.uk/thread...in-speed-realistic.236424/page-2#post-5831524