Blog: 1938TS vs. Class 483 - What's the difference?

The names 'Class 483' and '1938 Tube Stock' are frequently used interchangeably, including within this group, when referring to the units currently in operation on the Isle of Wight. However, whilst the Class 483 fleet is comprised of former 1938 Stock cars, there are in fact numerous differences that set one apart from the other. The most obvious of these is the formation of the units - A 1938 Tube Stock set was formed into either Three (DM/T/DM) or Four (DM/T/NDM/DM or DM/T/SNDM/DM - These abbreviations are explained at the end of this post) car sets, whilst the Class 483 units have only ever run as two car units (formed of two DMSO), though sometimes multiple units have been coupled to form longer trains - an exceptionally rare practice in recent times due to the drastically reduced size of the operational fleet. Other differences are listed below:

​1938 Tube Stock

• ​Separate 'Weak Field' Flag to reduce allow the traction motors to spin more freely.
• Brake controller featuring disc valves.
• Speedometer mounted on a panel to the left of the Motorman's window.
• Duplex air pressure gauge mounted                 alongside brake controller.
• ​Compressor mounted on trailer car.
• Deep, mellow-sounding whistle.
• Five marker lights on each cab end, for route indication purposes.
• Additional handrails on saloon partitions.
• Lighting from bulbs with frosted glass shades.
• 'Spring Hangers' for the benefit of standing       commuters.
• Padded leather armrests on longitudinal seats.
• Cerulean Blue interior paintwork.

​Class 483

• ​'Weak Field' setting operates automatically
• ​Altered Acceleration rate.
• ​Brake controllers replaced by some taken from 1962 Tube Stock, featuring poppet valves.
• Replacement speedometer mounted on a new panel in place of the original duplex air pressure gauge.
• Replacement twin air pressure gauges mounted on new panel to the left of the Driver's window.
• Compressor moved to Driving car.
• Replacement windscreen wiper.
• Replacement high-pitched whistle.
• Additional draft deflection around end doors.
  
• Replacement Driver's seat with additional heater.
• Original maple floor replaced with linoleum.
• Handrails added to cab side doors.
• One marker light replaced by a headlight, two removed and blanked over.
• Modified saloon partitions.
• Fluorescent Tube Lighting.
• Plain light blue and white interiors.
• Updated door opening and closing buttons.

The above information was gleaned from photographs and from a 2008 post by Mark Brinton, who has worked with these units. As can be seen, many of the differences may be found in the Motorman/Driver's cab, but there are plenty to be found in the passenger saloons as well. Despite this, the LTTG is likely to make cosmetic changes to some areas of any unit that we acquire in order to represent a unit in London Transport condition, as is more appropriate for the Epping Ongar Railway.

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Glossary of Abbreviations

• DM - Driving Motor. These are situated on the outside ends of a 1938TS unit.
• ​T - Trailer. There was one of these in each 3/4-Car 1938TS unit.
• NDM - Non-Driving Motor. These were found in 4-Car 1938TS units to provide additional power.
• SNDM - Special Non-Driving Motor. As per the NDM cars, but with additional controls for the Guard.
• DMSO - The classification given to the DM cars that form the class 483s, meaning Driving Motor Second Open. As London's tube lines only featured one class by the time the 1938TS was built, and all featured open saloons, there was presumably seen to be no need to describe these in the car's classification.