Train 419 004 is a single carriage electric multiple unit, in unbranded Network SouthEast livery. The manufacturer is Bachmann and the catalogue number is 31-268. The real train was designed to carry mail, parcels and luggage. A great article about the real trains can be viewed at http://www.semgonline.com/ and also at http://www.kentrail.org.uk/
This picture shows 419 004 berthed in one of the sidings used in the shunting puzzle. Note the detail including the air horns on the roof and the hand rails.
The real 419 004 appears to have been preserved after it was retired from use and various sources suggest it resides at the Mid Norfolk Railway