Is There An ERTMS-based Solution To The Digswell Viaduct?
Consider.
- Airliners have been flown automatically and safely from airport to airport for perhaps four decades.
- The Victoria Line has been running automatically and safely at over twenty tph for five decades.
- I worked with engineers developing a high-frequency sequence control system for a complicated chemical plant in 1970.
We also can’t deny that computers are getting better and more capable.
For these reasons, I believe there could be an ERTMS-based solution to the problem of the Digswell Viaduct, which could be something like this.
- All trains running on the two track section over the Digswell Viaduct and through Welwyn North station would be under computer control between Welwyn Garden City and Knebworth stations.
- Fast trains would be slowed as appropriate to create spaces to allow the slow trains to pass through the section.
- The driver would be monitoring the computer control, just as they do on the Victoria Line.
Much more complicated automated systems have been created in various applications.
The nearest rail application in the UK, is probably the application of digital signalling to London Underground’s Circle, District, Hammersmith & City and Metropolitan Lines.
This is known at the Four Lines Modernisation and it will be completed by 2023 and increase capacity by up to twenty-seven percent.
I don’t think it unreasonable to see the following numbers of services running over the Digswell Viaduct by 2030 in both directions in every hour.
- Sixteen fast trains
- Four slow trains
That is one train every three minutes.
Currently, it appears to be about ten fast and two slow.
As someone, who doesn’t like to be on a platform, when a fast train goes through, I believe that some form of advanced safety measures should be installed at Welwyn North station.
Conclusion
It will surely be more affordable to use clever signalling and train sequencing, than rebuilding the viaduct with four tracks.
The Anonymous Widower 
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Thameslink already has ATO and presumably once ERTMS is installed one ECML they will be able to improve capacity. I believe a big part of the problem is the two Welwyn tunnels mess up the headways which ERTMS may solve but not necessarily as trains being detained in tunnels is frowned up hence no signals if possible. I would have thought 90/100mph S&C in the 4-2-4 track sections would help as well
Comment by Nicholas Lewis | September 15, 2023 |
I wouldn’t be too surprised to find out that getting it right, is no more difficult than getting merging the two Northern branches of Thameslink or handling the trains through Paddington.
Comment by AnonW | September 16, 2023 |
https://youtu.be/WJkCgIdmWI ??
Comment by fammorris | September 16, 2023 |
Aka moving block signalling.
I think some improvement could be had by phasing the trains and slowing some to create gaps, however any mistakes could result in a collision on the viaduct, derailment onto the opposite track and / or off the viaduct.
OTOH AIUI SNCF manage it for TGVs.
Regards
Mark
mclayton@btinternet.com mclayton@btinternet.com
PS creation and log in to an account now seems necessary to comment, and IIRC WordPress pester you if you do. RMC
Comment by Mark Clayton | September 16, 2023 |
WordPress I suspect is getting entangled in red-tape insisted on by do-gooders.
Comment by AnonW | September 16, 2023 |
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