Signalling problems at Cannon Street

[MrB]

Appears to be a recurring issue at Cannon Street, Southeastern have had a 'signalling problem' there happen almost every day for a week or so. Anyone have any insight as to what's going on?

 

[E27007]

LB to Cannon Street "branch" used Solid Stare Interlocking system in contrast to the Relay interlocking system for the rest of LB area, if the SSI system was not replaced during LB Thameslink project then the Cannon Street SSI system is probably 30 years old now

 

[rower40]

Look, I know we've all done typos from time to time, but I just love this one:

LB to Cannon Street "branch" used Solid Stare Interlocking system in contrast to the Relay interlocking system for the rest of LB area, if the SSI system was not replaced during LB Thameslink project then the Cannon Street SSI system is probably 30 years old now

The sort of thing that Paddington might use?
Kaboom Tish and so on and so on.
Albeit that Paddington was upgraded from SSI to Smartlock a few years ago, though the data remained largely unchanged.

 

[WizCastro197]

It has occurred again today, this time outside London Bridge, doesn't indicate whether it is in the northbound or southbound location, so therefore could have nothing to do with CS.

Service disruption | Southeastern

If you are travelling you can find out the latest information about our services and see if there are any disruptions that might affect you.

www.southeasternrailway.co.uk

Hide details
Due to a fault with the signalling system at London Bridge, trains running through this station may be cancelled, delayed or revised.
Disruption is expected until the end of the day.
What's happened?
A fault has occurred with the signalling system outside of London Bridge.
Response staff have been unable to carry out repairs because of the nature of the work involved. Repairs will be carried out at the end of service.
How does this affect my journey?
Trains via London Bridge will be delayed or cancelled with some trains being diverted to Victoria / Cannon Street.
What do I need to do?
Please allow extra time to complete your journey.
You may use your ticket at no extra cost on London Underground services between:

• London Bridge
• London Cannon Street
• London Charing Cross
• London Victoria

 

[43066]

so therefore could have nothing to do with CS.

I was on a Ch+ train that was diverted into CST this afternoon which perhaps suggests a different fault.

 

[WizCastro197]

I was on a Ch+ train that was diverted into CST this afternoon which perhaps suggests a different fault.

Yes, the incident page did suggest trains were being diverted into Cannon Street rather than away from it, which then again suggests something other than Cannon Street is directly affected.

 

[E27007]

Look, I know we've all done typos from time to time, but I just love this one:

The sort of thing that Paddington might use?
Kaboom Tish and so on and so on.
Albeit that Paddington was upgraded from SSI to Smartlock a few years ago, though the data remained largely unchanged.

My excuse is is the "t" and the "r" keys on the keyboard are neighbours!

It has occurred again today, this time outside London Bridge, doesn't indicate whether it is in the northbound or southbound location, so therefore could have nothing to do with CS.

Service disruption | Southeastern

If you are travelling you can find out the latest information about our services and see if there are any disruptions that might affect you.

www.southeasternrailway.co.uk

Cannon Street branch probably too risky to implement red-zone SSOW, S&T staff have to wait until end of servi9ce to get stuck in to the fault

 

[Stephen42]

It has occurred again today, this time outside London Bridge, doesn't indicate whether it is in the northbound or southbound location, so therefore could have nothing to do with CS.

Service disruption | Southeastern

If you are travelling you can find out the latest information about our services and see if there are any disruptions that might affect you.

www.southeasternrailway.co.uk

Trains leaving Charing Cross haven't used platform 7 at London Bridge since around 12:30 using only platform 6, 7 is being used for turnback only. Network Rail have said it's a switch issue that will be dealt with at end of service.

 

[Nicholas Lewis]

Trains leaving Charing Cross haven't used platform 7 since around 12:30 using only platform 6, 7 is being used for turnback only. Network Rail have said it's a switch issue that will be dealt with at end of service.

Aint no P7 at Charing Cross presumably you mean Cannon St?

 

[Stephen42]

Aint no P7 at Charing Cross presumably you mean Cannon St?

Oops forgot to mention London Bridge is where platform 7 can't be used in the usual direction, edited now.

 

[Bald Rick]

LB to Cannon Street "branch" used Solid Stare Interlocking system in contrast to the Relay interlocking system for the rest of LB area, if the SSI system was not replaced during LB Thameslink project then the Cannon Street SSI system is probably 30 years old now

The Cannon St SSIs were replaced in 2017 as part of the London Bridge rebuild.

The problem has been an intermittent track circuit failure. Intermittent failures like this in complex trackwork are particularly difficult to diagnose and fix.

 

[Nicholas Lewis]

The Cannon St SSIs were replaced in 2017 as part of the London Bridge rebuild.

The problem has been an intermittent track circuit failure. Intermittent failures like this in complex trackwork are particularly difficult to diagnose and fix.

never got why they didn't go down the axle counter route for Thameslink

 

[Bald Rick]

never got why they didn't go down the axle counter route for Thameslink

at the time it was designed the evaluators / interlocking would not have been able to cope with the quantity of counts required. 12 car trains, every 2 mins (at times) in sections 2-300m long. Also the potential for miscounts is high due to the frequent stopping (and expected stopping just in rear of a station).

London Bridge pioneered the use of the EBI-400 jointless track circuit on plain sections, which has proven to be extremely reliable, and very few block joints, which rather simplifies Pway maintenance and bonding of course

 

[Nicholas Lewis]

at the time it was designed the evaluators / interlocking would not have been able to cope with the quantity of counts required. 12 car trains, every 2 mins (at times) in sections 2-300m long. Also the potential for miscounts is high due to the frequent stopping (and expected stopping just in rear of a station).

Oh axle counters aren't the total panacea after all!!

London Bridge pioneered the use of the EBI-400 jointless track circuit on plain sections, which has proven to be extremely reliable, and very few block joints, which rather simplifies Pway maintenance and bonding of course

Guess they are the small yellow boxes in the 4ft?

 

[E27007]

at the time it was designed the evaluators / interlocking would not have been able to cope with the quantity of counts required. 12 car trains, every 2 mins (at times) in sections 2-300m long. Also the potential for miscounts is high due to the frequent stopping (and expected stopping just in rear of a station).

London Bridge pioneered the use of the EBI-400 jointless track circuit on plain sections, which has proven to be extremely reliable, and very few block joints, which rather simplifies Pway maintenance and bonding of course

Those track circuit system arer good for plain line, but what of the S&C? What type of circuitry was used for S&C in Cannon Street?,

 

[Bald Rick]

Those track circuit system arer good for plain line, but what of the S&C? What type of circuitry was used for S&C in Cannon Street?,

I can’t remember, unfortunately.

 

[MrB]

The Cannon St SSIs were replaced in 2017 as part of the London Bridge rebuild.

The problem has been an intermittent track circuit failure. Intermittent failures like this in complex trackwork are particularly difficult to diagnose and fix.

Thanks for the colour on this.