vacuum braked vehicles piped to the engine. (F) Express freight, livestock, or ballast train not fitted with continuous brake. (H) Through freight or ballast trains not running under C, D, E or F conditions. (J) Mineral or empty wagon train. (K) Pick-up branch freight, mineral or ballast train. (G) Light engine(s) with not more than two brake vans. The classes are periodically revised, and , the classes have been: Express passenger train; nominated postal or parcels train; breakdown or overhead line equipment train going to clear the line (headcode 1Z99); traction unit going to assist a failed train (1Z99); snow plough going to clear the line (1Z99) Ordinary passenger train; Officers' special train (2Z01) Freight train if specially authorised; a parcels train; autumn-railhead treatment train; empty coaching stock train if specially authorised Freight train which can run up to 75 mph (120 km/h) Empty coaching stock train Freight train which can run up to 60 mph (95 km/h) Freight train which can run up to 45 mph (70 km/h) Freight train which can run up to 35 mph (55 km/h) train; other passenger train if specially authorised Light locomotive or locomotives Destination letters For long-distance trains, the country is divided into areas based upon the old British Rail regions. Each one is assigned a letter as follows: E: Eastern L: Anglia M: Midland O: Southern S: Scotland V: Western A train going from one region to another is given the letter of the destination region in its headcode. Prior to 1967 N was used to signify trains destined for the erstwhile North Eastern region. For trains internal to a region, the remaining letters can be used to indicate either: A destination zone inside that region, or A route within that region. Some areas within the Midland region are: A: London Euston or London Marylebone D: North Wales G: Birmingham H: Manchester C: London St Pancras (via Derby) D: London St Pancras (via Nottingham) F: Liverpool C: Cumbrian coast and Windermere While on the Western: A: London B: South Wales (e.g. Cardiff or Swansea) C: Bristol and West of Bristol (e.g. Exeter, Plymouth or Penzance) via Bristol TM or Westbury D: Oxford F: Cardiff to South coast of England and return G: Service to Cheltenham via Kemble H: Services via Bristol Parkway (eg. Penzance to Paddington via Bristol TM (routed via Hullavington)) J: Services between Reading & Basingstoke, or services calling