In Great Britain, the Sectional Appendix is a railway document compiled by Network Rail and is the official definition of railway infrastructure, giving a detailed description of all railway lines owned by Network Rail. It has traditionally been published in printed format, originally as a bound book and subsequently in loose-leaf format, for ease of updating.
In earlier years, instructions to traincrews relating to the operation of the railway were included within the working timetables. As the volume of instructions increased, they later came to be published in a separate document, known in full as the "Sectional Appendix to the Working Timetable" or similar.
There are modules for different areas, e.g. KSW2 covers Kent and Sussex. Each module may be divided in a similar way to the following sections:
Section 1: Route Module
Outline maps providing a general overview of the route showing lines, station names, and reference numbers. The numbers relate to pages in the detailed Table A diagrams.
- Exceptionally poor rail adhesion
This is a list of known areas for exceptionally poor railhead conditions. It states the route, location, lines affected, and the mileage references between which it occurs.
- Table A diagrams
This section comprises the main bulk of the module, and contains detailed maps. Information available includes;
- Name, maximum speed and direction of running lines
- Location of junctions and crossovers, and the maximum speed across them
- Name of Signal box/signalling centre controlling the lines
- NRN and Cab Secure Radio area coverage details
- Name and location of stations, platform identities and the maximum number or coach lengths they can accommodate
- Location and names of bridges, crossings and all significant infrastructure
- Location of sidings, yards, sheds, stabling and maintenance facilities
- Location of Electrical control rooms, and type of Traction current supply where applicable
- Location of Electrical substations and Track paralleling huts where applicable
- Special Working Arrangement
Special arrangement is a condition where a speciific location requires there to be an operational variance to the Rulebook, or an addition to it. This section details a route, locations where the arrangement begins and ends, the type of train this applies to, the line affected, and details of the operation.
Section 2: Route Availability
This is a list of which train types are permitted to travel over each route referenced to Table A. It specifies every class of train allowed, sectionalised by type;
- Route Clearance of Diesel Multiple Unit Trains
- Route Clearance of Electric Multiple Unit Trains
- Route Clearance of Coaching Stock
- Route Clearance of Locomotives
Section 3: General Instructions
Provides general information pertaining to operations over the whole area/route.
Section 4: Local Instructions
Provides detailed information relating to specific practices at given locations.
National Electronic Sectional Appendix
The "National Electronic Sectional Appendix" (NESA) is an online alternative to hard copy Sectional Appendices, although the latter are still being published and can be bought on-line, direct from Willsons Printers of Newark. Willsons also supply the various parts of the Rule Book in printed form and other items such as the AC Electrified Lines Instructions.