A big issue is that what typifies semi-fast services North and South of the river on individual routes varies quite a bit. On the BML routes a big category in "Semi-fasts" is fast to East Croydon then all stops e.g. the East Grinstead* which is a bit different to north of the Thames
The number of potential fast /semi-fast / stoppers each side of the Thames doesn't match hence there have to be compromises. Ditto 12car and 8 car capable routes and then throw in DfT not ordering enough 12 car.
Hence there will always have to be some "random" joinings it is impossible not to.
*The limited stop service to Oxted is provided by the Diesel 171s as the acceleration of DMUs is much worse hence the better acceleration of EMUs is used for the all stop service.
There seems to be quite a lot of lack of understanding of infrastucture issues on the network in these discussions. The Sussex route pretty much wins on the number of complex infrastructure interactions.
The stopping pattern via Oxted is literally nothing to do with the diesel fleet acceleration (the 171s, as I recently posted elsewhere, are so constrained by timetable issues caused by rubbish infrastructure layouts that any semblance of acceleration is more of a hindrance than a help, and as the current Marshlink timetable shows, they’re fine for stopping services).
The former Southern peak extras from London Bridge to East Grinstead, and vice versa, were simply extended through the TL Core, as had always been intended. The SN services had provided extra capacity into London from the Surrey commuter belt for some time, and it’s an awful lot more efficient to send them through London than it is to terminate them there, although one or two actually still do. Part of the problem with those signalling issues during the early bit of the LBG rebuild was that the stock for those East Grinstead services was still turning back in Platforms 10-15, which put those platforms absolutely at capacity in the peak, such that there was no wriggle-room. In the end the people of the suburban lines through Peckham Rye drew the short straw and ended up experiencing the wonders of South Bermondsey terminators, resulting in half of their services running near-enough empty and disgorging three people into the back of an especially miserable football stadium car park, and the other half being wedged solid with people going to central London.
But I digress...
Probably an unrelated (and silly) question but may save another thread.
But how come the South Croydon to Milton Keynes service isn’t intergrated into Thameslink as a sort of “Thameslink 2”? Thereby creating a Thameslink network, on thru the city, the other via Kensington
Sorry for this question, just genuinely curious
I’ve always thought it to be a lost opportunity. There are a number of logical extensions, some of which I’ve posted elsewhere.
My idea has always been for the line to be resignalled at higher capacity so that the same LO services as today could run, but with a stable increase in longer-distance services around those.
Total Thameslink meltdown on the GN side today due to a fatality earlier. Some massive gaps in the service at many stations.
Which wasn't helped by a points failure between Gatwick Airport and Three Bridges too which impacted on the MML too, pretty much nothing but cancellations between Bedford and Luton although they did manage to get a hourly service running and reinstated one service in the time period I noticed.
TL did quite well to run as much as they did... in fact, I was quite impressed that anything at all moved. The Network Rail response to the fatality couldn’t really have been any slower (not 100% their fault, by any stretch of the imagination, but lessons will probably “be learnt” about where to put their resources). LNER also had a broken down train, and one of the 700s briefly conked out near to the fatality.
