Thank you for Greg Scott to provide the following information:
Headcodes were used by signalman to identify the different train services passing by their signalbox. In 1976, however, the use of headcodes was discontinued and they were no longer displayed on the front of trains.
They are still used being the scenes though, within the modern signal box. This list is intended to show what headcodes consist of and mean.
A headcode consists of four characters that mean different things:
Classification of Trains
| 1X00 | Express Passenger Train |
| 1X00 | Newspaper Train |
| 1X00 | Post Office Train |
| 1X00 | Breakdown Train |
| 1X00 | Rescue Train |
| 1X00 | Snow Plough |
| 2X00 | Local Passenger Train |
| 2X00 | Breakdown Train (Not to be used) |
| 2X00 | Officer's Special Train |
| 3X00 | Parcel Train (90mph +) |
| 4X00 | Freight & Parcels Train (60-89mph) |
| 5X00 | Empty Coaching Stock |
| 6X00 | Freight & Parcels Train (50-59mph) |
| 7X00 | Freight & Parcels Train (40-49mph) |
| 8X00 | Freight & Parcels Train (- 39mph) |
| 8X00 | Sandite or De-Icing Train |
| 9X00 | Freight Train (Not fully fitted) |
| 9X00 | Eurostar Train |
| 0X00 | Light Locomotive |
General Destination Codes
| 0E00 | Eastern Region |
| 0L00 | Anglian Region |
| 0M00 | Midland Region |
| 0O00 | Southern Region |
| 0S00 | Scotland |
| 0V00 | Western Region |
| 0X00 | Royal Trains, Out of Gauge or Exceptional Loads |
| 0Z00 | Excursion, Military & Special Services |
Standard Headcodes
| 0F70 | Light Loco to Old Oak Common |
| 0F71 | Light Loco to Reading |
| 0F75 | Light Loco to Westbury |
| 0F76 | Light Loco to Exeter |
| 0F77 | Light Loco to Laira |
| 0F78 | Light Loco to St. Blazey |
| 0F79 | Light Loco to Penzance |
| 0F80 | Light Loco to Gloucester |
| 0F84 | Light Loco to Cardiff Canton |
| 0F85 | Light Loco to Margam |
| 0F86 | Light Loco to Landore |
| 0F90 | Light Loco to London |
| 0F91 | Light Loco to West of England |
| 0F92 | Light Loco to South Wales |
| 0E00 | Light Loco to East England |
| 0L00 | Light Loco to Anglia |
| 0M00 | Light Loco to Midlands & North West |
| 0O00 | Light Loco to South England |
| 0V00 | Light Loco to West of England & South Wales |
| 1Z08 | Structure Gauging Train (Not Operable) |
| 1Z99 | Breakdown Van Train |
| 2Z01 | Officer's Special Train |
| 2Z99 | Breakdown Van Train (Not to be used) |
| 6Z08 | Ultrasonic Test Train (Not Operable) |
| 7Z06 | Matisa Track Machine |
| 8Z06 | Matisa Track Machine (With Outriggers Extended) |
| 8Z08 | Ultrasonic Test Train (Testing) |