A train description (TD) is a four character reference given to each train to identify them to the signaller. They are shown on the display and will normally move along as the train progresses.
Descriptions are usually of the form 1N54. The first character (figure) represents the classification of the train. This can be useful to a signaller as it can give an indication of the type of train and the maximum speed that the train can travel at. The table below defines the classification of trains :-
| Class | Description |
|---|---|
| 0 | Light Locomotive or locomotives |
| 1 | Express passenger train, Nominated postal or parcels train, Breakdown or overhead line equipment train going to clear the line or returning from there (1Z99), Traction unit going to assist a failed train (1Z99), Snow plough going to clear the line (1Z99) |
| 2 | Ordinary passenger train, Breakdown or overhead line equipment train not going to clear the line (2Z99), Officers special train (2Z01) |
| 3 | Freight train which can run at more than 75mph, Parcels train, Authorised ECS (Normally an ECS train that will form a peak service on arrival at its destination) |
| 4 | Freight train which can run up to 75mph |
| 5 | ECS (Empty Coaching Stock) train |
| 6 | Freight train which can run up to 60mph |
| 7 | Freight train which can run up to 45mph |
| 8 | Freight train which can run at, or is timed to run at 35mph or less |
| 9 | International train or (depending on period) Unbraked freight, nominated express passenger train |
The second character (letter) determines the destination or route. These depend on the area in which the train is operating. Some destination codes are the same throughout the country, being especially applicable to long distance trains. Some of these are shown below :-
| Character | Destination area or region |
|---|---|
| E | To the Eastern Region |
| L | To the Anglia Region (when it was separate) |
| M | To the Midland Region |
| O | To the Southern Region |
| S | To the Scotland Region |
| V | To the Great Western Region |
| X | Out-of-gauge train. Also Royal train |
| Z | Special trains |
Each region then has its own codes for intra-regional trains. For example, at one time Eastern Region used:
| Character | Destination area or region |
|---|---|
| A | To the London Division |
| D | To the Doncaster Division (I think) |
| N | To the Newcastle Division |
The third and fourth characters are the individual train reporting number, used to identify each train in that class using the same destination or route.
SimSig timetables may contain more than one train with the same description. These are distinguished by using an extended description of the form 1N54A or 1N54-3. Only the first four characters appear on the display. In real life each train is also only shown as four characters, but internally has a longer identity which bears no resemblance to the train description.
Last edited by GeoffM on 15/09/2016 at 03:01