Could digital signalling systems be used as a workaround for power supply limitations?

[The Planner]

The Great Western Mainline between London and Reading is congested infrastructure.

It isn't, Castlefield, WCML at the south end, Wrexham to Bidston, and parts of the ECML from December.

 

[HSTEd]

I suppose the question must be asked, would altering the signalling system to do this be more or less expensive than buying a bunch of (almost) off the shelf static frequency converters and altering the 25kV system so that all feeders are in parallel? That would likely achieve substantial increases in capacity without further grid feeders or wholesale rewiring or anything like that.

Altering signalling systems is very very expensive at the end of the day

 

[zwk500]

Network Rail western sectional appendix refers to ERTMS L2 between Ealing Broadway and Heathrow/Stockley Bridge Junction, when Great Western Railway refers to it as ETCS L2.

NR follows the RSSB terminology because it aligns with the rulebook (which RSSB publish). It's not helped by the ERTMS website referring to ERTMS/ETCS as interchangeable.

 

[MarkyT]

Incorrectly. ETCS and GSM-R are separate components of ERTMS. The RSSB refer to ERTMS as their position is that the safety system involves both ETCS and GSM-R. However there are non-safety related components of ERTMS as well.

The way I rationalise it is that ETCS messages for movement authority and infrastructure characteristics required for safe movement can be carried by GSM-R or other vectors such as balises or track loops. The messages use the same ETCS message protocol or 'language', however the data is passed. GSM-R radio can and is used for other purposes, notably voice comms, so that bearer is considered part of wider ERTMS, in Level 2 carrying ETCS protocol messages between ETCS sub-systems as well as voice.

 

[zwk500]

The way I rationalise it is that ETCS messages for movement authority and infrastructure characteristics required for safe movement can be carried by GSM-R or other vectors such as balises or track loops. The messages use the same ETCS message protocol or 'language', however the data is passed. GSM-R radio can and is used for other purposes, notably voice comms, so that bearer is considered part of wider ERTMS, in Level 2 carrying ETCS protocol messages between ETCS sub-systems as well as voice.

For the rulebook, because of things like e.g. GSM-R is used for non-signalling communications, I can see the argument that 'ERTMS Regulations' is a better description than 'ETCS Regulations' because the railway is ultimately a traffic system not a signalling system, and this would extend to the sectional appendix as well. However the part of ERTMS that controls the safe movement of trains is ETCS.

However, as mentioned, there is also a 'Traffic management' layer of ERTMS that is entirely non-safety related. It's about optimising regulation of trains and things like that, with live timetable adjustments and so-forth

 

[Class15]

It isn't, Castlefield, WCML at the south end, Wrexham to Bidston, and parts of the ECML from December.

I wonder why the following aren’t congested infrastructure?

North London line
Southern Midland Main Line
Coventry Corridor

 

[zwk500]

I wonder why the following aren’t congested infrastructure?

Southern Midland Main Line

It was until 2024:

Information for operators - Network Rail

Key documents to guide you through how we do business with our customers, including both existing & potential freight train operators.

www.networkrail.co.uk

https://www.networkrail.co.uk/wp-content/uploads/2024/05/Midland-Mainline-Confirmation-of-Revocation-of-the-Declaration-of-Congested-Infrastructure-3-May-2024.pdf

03 May 2024 Revocation of Declaration of Congested Infrastructure: Midland Mainline (Leicester to Cricklewood via Market Harborough and Corby)

 

[The Planner]

I wonder why the following aren’t congested infrastructure?

North London line
Southern Midland Main Line
Coventry Corridor

Because there haven't been enough proposals in terms of an uplift to say you cannot fit trains in. MML was, but it was revoked last year.

 

[Bald Rick]

I wonder why the following aren’t congested infrastructure?

North London line
Southern Midland Main Line
Coventry Corridor

There’s a very clear definition (described in the Network Code), which these lines don’t meet, although the NLL might be on the cards soon.

 

[Technologist]

Well if we are talking about static batteries, you could go for some pretty esoteric battery technologies.

Sodium-Sulphur batteries are potentially really cheap per kilowatt hour and have pretty good performance characteristics. They are just rather hard to keep on a moving vehicle due to being at 200 celsius.

In a substation it would scarcely matter.

Or we could just use LFP or eventually sodium ion types that are cheap as chips, mass produced and available in variants that have 10,000 cycles lifetime. When they fall down we can then replace them with batteries that are cheaper and last longer ad infinitum.

I used to work somewhere where we had knowledge of working with and developing ZEBRA batteries which are similar in characteristics and I wouldn't recommend working with them ever.