Glossary

Browse the A-Z below for some rail-specific terms that are used in this website, together with their meanings.
 

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  • T

  • T-12

    The ability of passengers to obtain travel information, make reservations and book tickets in advance is affected by changes to the timetable caused by Network Rail taking possession of lines in order to maintain, renew and enhance the network. Under Condition 9 of its network licence, Network Rail is required to ensure that accurate timetable information is available to train operators at least twelve weeks in advance. 

  • TfL

    Transport for London

  • TOC on TOC

    Where a delayed train service of one train operator delays those of another train operator.

  • TOCs

    Train operating companies: run the (passenger and freight) trains and services on the network. The representative body for the passenger operating companies is the Association of Train Operating Companies (ATOC).

  • TOPS

    Total operations processing system.

  • TPWS

    Train protection and warning system.

  • Track

    Section 83(1) of the Railways Act 1993 defines “track” as follows:
    “any land or other property comprising the permanent way of any railway, taken together with the ballast, sleepers and metals laid thereon, whether or not the land or other property is also used for other purposes; and any reference to track includes a reference to:
    (a) any level crossings, bridges, viaducts, tunnels, culverts, retaining walls, or other structures used or to be used for the support of, or otherwise in connection with, track; and
    (b) any walls, fences or other structures bounding the railway or bounding any adjacent or adjoining property”.

  • Track circuit

    Track circuits are designed to detect the presence of a train, by use of an electrical circuit which is completed by train wheels and axles.

  • Track circuit failure

    Failure of a track circuit or associated equipment, including axle-counter failures.

  • Track geometry

    The level and alignment of the track.

  • Train

    Section 83(1) of the Railways Act 1993 defines “train” as follows:
    “(a) two or more items of rolling stock coupled together, at least one of which is a locomotive; or
    (b) a locomotive not coupled to any other rolling stock”.

  • TRUST

    Train running system TOPS.  A train running and punctuality monitoring system, mainly fed by automatic inputs from signalling systems.

  • TSR

    Temporary speed restriction imposed for safety reasons. This can arise from the poor condition of track, structures, earthworks, hot weather effects, or following track relaying until the track bed is stabilised.

  • TSR (COT)

    A type of Temporary speed restriction that has been imposed specifically due to the poor Condition of track (COT).