TS 7455

TS 7455 is an electrotechnical vocabulary standard that collects terms and definitions for signalling and safety apparatus used on railways. It standardises the naming used in this technical field, so that core concepts such as interlocking, interlocking boxes, train sectioning, carriage arrangement, and various equipment are understood consistently.

Why terminology matters in railway signalling

Railway signalling and safety systems rely on tightly connected concepts such as route control, movement authority, and equipment interdependence. Clear definitions help reduce the risk of misinterpretation between manufacturers, operators, and technical teams. The focus of this standard is therefore conceptual consistency: it is about the meaning of the terms used in the domain, rather than laying down a detailed design or operating code for the equipment itself.

Concept groups covered by the standard

• General concepts and basic technical terminology used in railway signalling
• Terms relating to interlocking and interlocking boxes
• Concepts connected with train sectioning
• Definitions associated with carriage arrangement and various apparatus

In general technical usage, interlocking refers to the dependency logic that prevents unsafe or incompatible combinations between signals, points, and related devices. Train sectioning is a basic operational concept describing how a line is managed in defined traffic-control sections. This standard is recorded as equivalent to IEC 50-31:1959, and the TS 7455 entry is currently marked as withdrawn; historically, however, it remains a useful reference for understanding electrotechnical railway terminology.