London Underground engineering stock

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A train carrying track ballast passes through Holborn.

Over the years, London Underground has acquired various types of engineering stock to help with the construction of new lines and maintenance of existing lines. Some of these wagons were inherited from its predecessors, many were built new and some were acquired second-hand from British Rail. Several types of specialist wagons have been used, which are described below.

1 Overview
2 Brake vans
3 Ballast and hopper wagons
4 Flat wagons
5 Rail wagons
6 Cranes and track machines
7 Specialist wagons

[edit] Overview

London Underground uses a numbering system, whereby the wagon number is prefixed with a letter, which designates the wagon's type. These are summarised below.

Wagon prefix	Meaning	Description
B	Brake van	Manned wagon used for guard's accommodation and for braking purposes. No longer used.
BW	Ballast wagon	Open wagon, for transport of ballast
C	Crane	Powerful crane for track laying/lifting and/or recovering de-railed rolling stock
DEC	Diesel-electric crane
DHC	Diesel-hydraulic crane
CM	Cement mixer wagon	Specialist flat wagon, with a cement mixer. These wagons have been modified and now form part of Tubelines's DISAB ballast sucking machines.
CW	Cable drum wagon	A short wagon for transporting cable drums through deep level tunnels. For signal wiring
FW	Flat wagon	Flat wagon, for transport of rails or sleepers Now only used in train formation with tampers 771,772 and 773.
FB	Flat brake	Flat wagon, with brake van compartment. No longer used.
GP	General purpose wagon	General purpose wagon
HD	High deck wagon	to carry a stack of track panels no more than 4 panels high.
HW	Hopper wagon	Hopper, for transport of fresh ballast
J	Jib carrier	Specialist flat wagon, for carrying the arm (jib) of a crane
JC	Jib carrier
JLE	Jubilee Line Extension	The same as General Purpose wagons (GP), used in the construction of the Jubilee Line Extension. Only difference is that the JLE's wagons have larger handbrake wheels.
MW	Match wagon	Wagons paired with the cement mixer wagons. Now used as GP wagons semi-permanently coupled together.
RW	Rail wagon	Specialist flat wagon, for transport of rails
SB	"Turbot" ballast wagon	Specialist ballast wagon, that will deliver ballast to the trackbed. Can also be used to transfer plant, used ballast or scrap.
TMM	Tamping machine	Ballast tamper for packing ballast to make lines more durable. Numbered 771, 772, 773 and 774. 771, 772 and 773 can only be transported through deep-level tunnels in train formation. 774 is for sub-surface lines only.
WPW	Well wagon	Specialist flat wagon, with lowered central section to enable larger loads to be carried. All have prefix JLE. Commonly known as a 'Low Loader'.^{[citation needed]}

[edit] Brake vans

London Underground has used various designs of brake van. They were used for the guard's accommodation and for braking purposes (when wagons in the train were not fitted with automatic brakes).

Two brake vans of interest were numbers FB578 and FB579. These were 'flat' brake vans, converted from flat wagons. The conversion consisted of building a small guard's compartment on one end of the flat wagon. Therefore, these wagons could be used for carrying small items, such as sleepers, in addition to their role as a brake van.

Several brake vans have been preserved. These are listed below.

Number		Year built	Builder	Preserved location	Comments
B	557	1935	Hurst Nelson	Buckinghamshire Railway Centre	-
B	560	1935	Hurst Nelson	Spa Valley Railway	-
FB	578	1935	Gloucester RC&W	Buckinghamshire Railway Centre	Converted from flat wagon F330