Should the Express services be categorised as a '1' service as opposed to a '9' thereby giving same priority as EMT up to Bedford?
How does a signaller know its an 'Express' ?
Short answer: the letters after the 9.
- 9Txx and 9Rxx run on the fast lines between St Pancras and St Albans (as do 9Lxx and 9Nxx in the peaks), mostly calling only at West Hampstead Thameslink
- 9Oxx and 9Vxx stop all stations between St Pancras and St Albans
- 9Pxx call all stations between St Pancras and Luton (except Kentish Town, Cricklewood and Hendon)
- 9Kxx in the peaks call all stations between St Pancras and Luton (outside the peaks start/terminate Kentish Town)
The other letters (9Jxx, 9Sxx, 9Uxx, 9Yxx) serve (or will eventually serve) the Great Northern side.
As
Sunset route said, when the number is 80-99 it generally signifies something unusual about that train - e.g. 9T86/88/90/92 call St Pancras - St Albans - Luton- Bedford only (and stay on the fast lines all the way to Bedford South Jn).
This is not a new idea - for years the signallers between Birmingham and Coventry have distinguished a Virgin Trains service (9Gxx down, 1Bxx up) from a London Midland stopping service (1Wxx/1Yxx) by letter rather than number.