ECML ready for IEP - electrical compatibility

[snowball]

This press release has appeared on Network Rail's site. I can't find an existing suitable thread.

https://www.networkrail.co.uk/feeds...ones-ahead-of-new-intercity-express-services/

Network Rail has completed two major infrastructure milestones on the East Coast Main Line (ECML) ready for the introduction of new InterCity Express Passenger (IEP) trains later this year.

The first is the completion of a gauge clearance project. The work means that the ECML and its diversionary routes spanning England and Scotland have been checked to make sure that the new trains have enough clearance to all lineside structures such as bridges and platforms, can pass other trains safely and that there is enough space for railway workers to stand beside the tracks when trains pass by.

As IEP trains are longer and have a different cross section to those currently in use, the gauge clearance was needed across over 1,700 miles of the route, including 3000 sets of switches and crossings, and 800 bridges and structures. These encompass London King’s Cross to Inverness, Aberdeen, Leeds, Hull, Harrogate, Skipton and Glasgow as well as diversionary routes such as London to Peterborough via Ely and Newcastle to Glasgow via Carlisle.

In addition, the project had to make over 40 separate modifications on the route. These ranged enormously in scale from simple relocation of pieces of lineside equipment like ground signals and speed signs which took a few hours, to much bigger modifications taking several months, such as demolition and reconstruction of platforms and bridges.

The second key milestone is the removal of a number of electrical boosters, which are incompatible with the new trains.

Critical to the safe running and overhead line compatibility of the new trains, the project saw 35 overlap booster transformers, which channel traction return current into the return conductor, removed from 12 locations, ranging from Finsbury Park in London to Berwick-Upon-Tweed in Northumberland. An added benefit of the project is the recycling of the booster transformers north of Newcastle. The large booster transformers in Northumberland alone resulted in 1.5 tonnes of copper turned into a £3k return.

Paul McKeown, Investment Director at Network Rail, said: “These two milestones show the sheer scale of work Network Rail is doing behind the scenes in readiness for the introduction of the IEP trains onto the ECML later this year.

“We’re making excellent progress on our IEP readiness programme, which is testament to the hard work of our teams out on the ground and we’re all excited to see the new trains introduced as they will really benefit passengers by providing thousands of extra seats.”

I was unaware until now that the booster transformers were incompatible with electric IEPs. Has this been known ever since the trains were ordered or is it a later discovery?

I thought I knew roughly what a booster transformer is, but what is an overlap booster transformer?

I believe the southern ECML was being converted to the autotransformer system anyway, but presumably this has not been done all the way to Leeds and Edinburgh. Have booster transformers also been removed where there are no autotransformers going in yet and if so what are the implications?

Are there other routes, already electrified with booster transformers, on which IEPs might run and which therefore require their removal?

Is any of this related to the early electromagnetic compatibility problems encountered on the GWR?

 

[Elecman]

I suppose the reason for removing them is to reduce the impedance in the supply circuit if the voltage drop at midpoints is becoming marginal at abnormal feeding situations with IEPs drawing full current.