ELL West Croydon fasts

A service fails PPM now if it skip stops, however one failed service could then result in the next service running on time rather than both failing. Thus skipping gets you 50% performance rather than 0%. For a metro network it's annoying but gives better service overall.

Unfortunately that crude measure takes no account of the number of people affected. My local TOC often skip-stops a with-flow peak working so that the return (contra-peak) service can run on time.

Once you get on the Up Fast at either Norwood Junction or Sydenham, there is no way to cross back over before the ELL flyover at New Cross Gate. A train running fast to New Cross Gate and then all stations will always be run on the Up Slow.

Even if TfL had money at the moment I can't see them spending it on something that would increase flexibility given that the present operating philosophy is to minimise the number of things that need maintaining even if it means there is reduced flexibility to recover from or work around disruption.

If they can't use them why would they sign them? They couldn't keep the knowledge current once learned anyway.
If a new set of points was installed such that LO services could access the ELL core from the fasts then there would be no benefit in not road training the drivers (but see my previous post on the likelihood of this happening)

New Cross Gate (ELL) drivers DO sign the fast lines. All the signals are in the same locations as the slow lines sharing signal gantries, only major difference is the 10mph higher line speed on the fasts. During severe disruption on a rather busy/stressful day a while back, I ended up diverting on to the Up Sussex Fast at Norwood Junction. Out of service at New Cross Gate and in to the Up Sussex Loop - where I was held for quite some time. I was then informed that I would be resuming my normal diagram from Crystal Palace. (Pre-May 2018 diagrams) I was then instructed to run in service from New Cross Gate Platform 3 (Down Sussex Fast), then cross over on to the Down Sussex Slow at Forest Hill, call at Sydenham and then terminate at Crystal Palace. It is for these kind of out of course situations that we sign them. It would be foolish not to.

If that is true, it’s quite amazing that someone needed to point it out!

Thats quite interesting as I'm sure I read somewhere (possibly London Reconnexions) that such measures (possibly for Thameslink or Crossrail) were in the performance regime weighted to be proportional according to either the modelled loading of the train and/or the station's patronage for that service, along with minimum mandatory levels of frequency. Perhaps such complex measures are not in use elsewhere at the moment? If so that is a great shame, as short-tripping and station skipping by their ad-hoc nature can be difficult to quantify and have a disproportionate affect on certain stations and sections.

May I ask which TOC is your regular?

Any failure to call at a station is counted as a failure. However with the ever busy national network a singe minutes delay can cause chaos if left unchecked and lead to hours worth of delays (I'm serious. I've seen a 3min delay on a weekend cause over a 100 minutes of delays as the ripples spread in an actual real world investigation). Those delays will be charged to someone. As a result here has to be a way to restore the service and missing out stops is better than the alternative which is a part or full cancellation.

Part of the move to right time running (or within 60 seconds) will require missing stops for a delay as short as 2mins going forward. Remember in the performance world on the mainline missing a stop is the same as being 60 seconds late in the right time world. This is why I don't support going to such a small metric.

The fasts are already pretty full of Thameslink/Southerns though - one every couple of minutes during the peaks - running at full pelt through Forest Hill and so on. Can't imagine GTR would be particularly happy to slow down for a 378 making up time. They have a lower maximum speed (75mph) compared to the 700s (100mph).

Fair enough. Still though, lots of trains on those lines without much slack time.

However going over any points to change tracks will be a significant chunk of capacity that will slow trains down regardless.

We need to remember that the original Thameslink timetable that NR developed was rejected in the end due to too many trains on the fast lines. This is why the Rainham and Orpington services was developed to reduce pressure on this section of track by reducing the proposed service by 4tph as modern planning simulations show it can't cope. In peak there is zero room without re signalling to provide better headways and that won't come any time soon.

During disruption, London Bridge to London Victoria trains will run Down Sussex Fast and crossover at Forest Hill when they're a fair bit behind schedule.