Six or seven minutes in both directions for Avanti Birmingham services; given that Milton Keynes is 3 tph, London's 5 tph (+ Overground), Manchester etc.'s a few trains per day and St. Albans – Hemel Hempstead makes more sense by bus, I don't think there's much need to time it around anything except at least one of the Birmingham services. The West London line service is the odd one out at Watford Junction, and almost if not everywhere in Greater London and just outside, in only being an hourly service.It is well timed to connect into services up and down the mainline during the off peak.
Watford Junction is ideal, but the key point would be to get the trains off the WCML SLows so Wembley Central it would be.Wouldn't Harrow & Wealdstone make more sense ? There's space for a bay platform on the east side which was the old Belmont branch platform and LNW stop the Tring and MK stoppers there so it would be an easier interchange for some places north of Watford.
You have 4tph from Watford Junction on the DC Lines, all the WCML Slows and Fasts let alone the trains from the St Albans City on Thameslink. It is the very definition of a turn up and go service, therefore 45 minute frequencies offer you a greater number of journey opportunities to London.Personally i'd prefer having a frequency that means me know that I can always make a connection towards London than having a frequency where its not certain if I can make a connecting train.
Although realistically I think you'd only change between St. Albans Abbey and City if going to e.g. Bedford, Gatwick or Brighton rather than London, and Watford Junction doesn't get one of the LNR Birminghams or the Trent Valley service., all the WCML Slows and Fasts let alone the trains from the St Albans City on Thameslink
How many people wish to travel from Birmingham to Croydon (or the reverse?)? I seriously doubt that it is very many. If they have to change at Croydon to travel further then what is wrong with changing in central London instead? Your suggestion seems more Crayonista "l think that this would be neat" than credible even for the Speculative thread.I think it would be great if the Milton Keynes to East Croydon service was reinstated and also made more frequent than hourly - possibly by being converted to Overground. I think if popular, it could take pressure off Euston whilst we wait for HS2. In addition, is there any possibility of a semi-fast Service?
I also think it that a one-seat service from Birmingham New Street to East Croydon (obviously not run by Overground) could be very, very interesting.
There's a lot of technical stuff that I don't know so feel free to pull this idea apart !!
To stop all slow line WCML services at a Willesden Jn low level would require 3 maybe 4 platforms, for which room is extremely tight at best.A bay at Wembley Central is a good compromise, but IMHO the gold standard is platforms at Willesden Junction. Then you possibly don't even need the Southern service at all - you can just use the WLL paths for more Willesden to Clapham LO services, and the WCML slow paths for more services into Euston. Unless there is no capacity into Euston for more services, of course.
My idea at Wembley would be that the relief lines (or at least one of them) would extend to the hypothetical bay platform independently of the WCML Slows, thus avoiding the conflicting move problem. If you were able to rebuild the OSD at Wembley Central you might be able to squeeze an 8-Car central terminating platform a la Tring between the slows. Either option obviously has a massive impact on the connections into the goods lines and so would be exhorbitantly expensive to do.The main downside I see at both Harrow and Wembley (and it's the same issue at Watford), is that the terminal bay is always on the outside of the up platform. This means entry into the bay when speed is slowest is a conflicting movement (abet, leaving when you're accelerating away isn't), but more importantly, the cross platform interchange you get is to go back south where you've just come from, not north, where you likely want to continue your journey, making them awkward interchanges.
I'd welcome a (semi)fast Tring / Milton Keynes to Wembley Central and Willesden Junction service as Hemel Hempstead – Paddington feels like a slow journey, even with Crossrail speeding up going via Euston, but of course converting the existing service to Overground would mean removing the existing slightly faster Wembley Central service instead.Terminating at Wembley Central seems rather pointless to me. It doesn't offer any new connections that you can't make by changing at Willesden Jn and apart from event days, I don't think there is any great demand for people south of the river to get to Wembley.
I agree, Wembley isn't really that helpful.Terminating at Wembley Central seems rather pointless to me. It doesn't offer any new connections that you can't make by changing at Willesden Jn and apart from event days, I don't think there is any great demand for people south of the river to get to Wembley.