The convention among train timers back in the days of OSNock et al was 16 passengers to 1 ton. However, people are heavier these days...
IIRC correctly BR assumed 16 pax and their luggage to the ton. Need to check what latest is e.g. for IET.
For the Torbay Express I assume 4 tons for the pax in a TSO and 3 tons for a FO and the buffet, a ton or two for staff and stores in the kitchen and say a couple of tons for tbe spare equipment in the support coach.
For horspower calcs you need to add the weight of the loco 'in working order' (coaled and watered, boiler full) although of course coal and water are constantly being consumed - until replenished.
So all in all if you get the correct weight within say 5 tons you are doing well.
On the National Preservation forum most of the chat comparing different runs simply refers number of coaches, which is a good yardstick, but needs to take account that a 10 coach train with mainly Mk1s on B4s or Mk2s can weigh the same as a 9 coach rake of heavy Pullmans (the MetCams are 38 - 39 tons).
That’s a good point actually.
