Serious disruption evening of 08th October

Hi Graeme, good to hear from you albeit under difficult events.

Sounds like a bad evening. Many of my friends were complaining this evening.

The potential track alteration may be possible although at times of disruption the bay roads are used a lot to short trip city trains so it may add to the problems although I see your point. If only the S-N reversal from plat 3 was still an option....

i think the faulty train should been withdrawn and sent to depot straightaway after KX issues
and i agree a stabling area to store out of service trains till its quieter time to remove faulty trains

well its important like other systems - example two bi direction lines if one is blocked then trains can go around the blockage - good examples of this - WMATA which uses single tracking often to bypass failed train or any issues or bypass the trackwork without blocking the line but few times lines has to suspend fully but this rare on WMATA

In the bigger picture it all boils down to cost. The question is always going to be what price contingency as against cost of estimated failures and/or delays each year. Crossovers and sidings cost money even if they are unused, there is the initial outlay, usually a very expensive one off cost, but the real killer in a tight budget is the ongoing cost of routine maintenance which is hard to justify if an asset is idle most of the time.
I have no doubt at all that the operating department would be overjoyed to have the utopian flexibility of unlimited spare track capacity, bidirectional signalling on all lines and even extra depots which would all make operations in a time of crisis far easier to handle. However, the more facilities the greater the initial outlay, the greater the maintenance cost and the more staff required to keep it all up to standard specification. More staff has its own costs such as the need for additional training resources etc. When money is tight one of the first things to suffer is spare capacity which gets longer maintenance intervals until it eventually falls into disuse through failing to meet the specification. Quite often the value of such facility can go unnoticed in good times when it is not required for long periods and is simply seen as an unnecessary drain on the budget.

I would respectfully suggest that empty sidings and additional reversing points are not so much out of favour as they are unaffordable in an age where everything costs too much and the reasons for that are far beyond the scope of this thread. From an engineering viewpoint I'd have been overjoyed for ever more equipment to install and maintain but service efficiency costs just as service inefficiency costs and what is affordable lies somewhere between the two. Unfortunately the purse strings are not necessarily controlled by those who are best placed to properly judge the true costs of an efficient and reliable public service. That of course is another tin of worms well beyond the scope of this thread!

It looks like, in the Bank redevelopment, that there is scope for a cripple siding on the approach to the old southbound platform.

Out of curiosity I have a couple of questions...

1 - Given that there are sidings at Moorgate and points just east of Kings Cross would it not have been easier to reverse the train to Moorgate sidings for later recovery rather than the long slow track to Wembley?

2 - Rather than crawl a defective train at 10mph is it not possible to stick it in neutral and get a empty working train behind to push it along more speedily?

They have the option to couple up and be assisted by A, C or D stock, but whether or not they can physically do so is another matter. It'd probably be a scenario they would like to avoid though. But the assisting train would have to be detrained, trip past signals to get closer, &c., &c.

Many of the Main Line Burst problems that have been occurring recently are as a result of the ACMs receiving no traction current through the loss of shoes and then the train being situated in such a way where any shoes that do remain are not on juice, or where they are, the train just cannot get the power it requires. Once the compressors on the train cannot charge up, the speed of the main line air loss is almost immediate and it goes down a lot quicker than with other stocks. Cue the SAPBs. And if that happens over gaps when you're already missing shoes, good luck. With regards to air defects, S stocks are fairly simple to negotiate – split the main line pipe into two by isolating it in the middle, see if you can get the leading cab to charge up (as the trains can run on one compressor to at least get it moving), then there are a few isolations you then have to make in order to get forward movement.

Similar but not, this was nearly the case with my train in July, where I had lost a large portion of posi shoes all along the right hand side of the train at Finchley Road on the south (they were taken off by a disused inductor rail). The TCMS however gave no indication of shoes having been damaged and a problem only became apparent when i was departing King's Cross, when the posi rail switches sides over to the driver's side, all the way until the home signals for Farringdon; I was unable to motor, and worried that I would stall between stations, I allowed the train to coast downhill into Farringdon before the air gauge immediately gave up the ghost, dropped to red and sat me down just metres from the stopping mark. The fact that the posi rail then moves back over to the other side for a few metres on the approach to Farringdon was my saving grace in the end as it allowed the ACMs to get some power back so I could get motors for a few seconds, but I could quite easily have stalled outside the station. I was also fortunate enough that once I'd detrained, I could work the train straight into Moorgate bay.

I see what people are saying about reversing KX or main line shunt at Baker, but as a driver, I wouldn't really want to take the risk of then stalling in the city trying to get to a siding and then completely locking it down. I think getting North of Baker Street does make some sort of sense. Even if it stalled between there and Wembley, at least you could still maintain a service between Wembley and the branch lines to some degree.

If a stepplate junction were being built, then yes. But the constraints of the site (in particulat the proximity of other tunnels) means that "plug and drill" is the preferred method - remove the tunnel lining, fill with concrete, and drill through on the new alignment. (more or less what you would do if you'd put a screw hole in a wall in almost, but not quite, the right place - you need to fill the old hole before you can drill the new one next to it.

Having personally experienced the frequency of services when WMATA is doing single tracking (or lack thereof--3 to 5 tph at most), I think that doing so unannounced on a weekday would result in dangerously overcrowded platforms very quickly.