I am looking at train around 7:30 to 8am southbound at wembley park. It seems that the 431 is a watford to baker street. It is useful to know the numbers so you can instantly say where the train has come from - and which may be busier or not.
Also can you explain train description e.g. WF0 or BK3.
The train numbers are only a useful guide to which service the train is operating during off peak periods, which on weekdays means only between the morning and evening peaks. At other times any train number can appear on any service.
The Met train descriptions split into two parts. The letters give the final destination while the digit indicates the stopping pattern e.g. fast or all stations. There have been several threads in the past that explain the meaning of each digit. districtdavesforum.co.uk/post/19331