In message , at 16:54:29 on
Mon, 1 Aug 2011, Paul Scott remarked:

What they said:

5.13.6 Following the completion of the Thameslink
Programme the following morning peak train service
(14 trains per hour) is anticipated as remaining in
operation into London King's Cross:

Cambridge stopping services, via WGC
- two x eight-car trains operated by Class 377
stock (maximum acceleration is particularly
important on this service group, given the
need for calls at Welwyn North)

Peterborough fast services
- two x 12-car trains operated by Class 365
stock

[The other 10 services are 2 x Kings Lynn IEP and 8 x long distance.]

So what, if any, Cambridge peak trains will go to Horsham?

The two mentioned in the OP that are going through to Horsham via the
yet to open ECML link to St Pancras LL. Those above are going to Kings
Cross - ie the mainline station. What's so difficult about all this?

At the moment, peak trains to Cambridge are much more like the normal
timetable, but longer and with a few extra stops. What you seem to be
describing are a couple of extra trains on a different route (from KX
not Horsham).

It's not "difficult", but it's taking a while to tease out the full
picture.

Meanwhile Colin doesn't think that one of the two 12car Horsham trains
off-peak will stop at the Cambridge rural stations (which something
must), nor indeed could does he think they could be described as
"semi-fast".

It seems to me that make 6 trains altogether:
2 x Thameslink, 12 car T/L stock,
2 x Kings Cross 'IEPs' from Kings Lynn via Cambridge,

New question: are both the IEPs going to be running to Kings Lynn, or
only 1tph like today? It seems a big jump from four cars per hour to ten
(assuming this is a 5-car IEP). And will they be adding a second 5-car
IEP unit for the Cambridge-London leg?

2 x Kings Cross 'stoppers' from Cambridge.

How that relates to today's service I'll leave to others, but surely
the whole point is that there doesn't need to be a one to one
relationship between what trains happen to run today and what happens
in 2018?

Agreed.
--
Roland Perry