What is the 'authority to proceed'?

Authority to proceed is the formal name for the permission or authorization that allows a driver to take a train into a section of track, in either block or non-block systems of working. It is also known as train working authority. In places where token block instruments are in use, block tokens constitute the authority to proceed. Normally in tokenless block working the authority is implicit in the aspects of signals, although it may be a paper form if signals are defective or missing, etc., or if signalling has been disrupted by equipment failure, floods, etc. In non-block working or under special circumstances, authority to proceed is physically given to the driver on a paper form, or conveyed to him by telephone or walkie-talkie.

Any form of authority to proceed which is in physical form (token, paper form, etc.) is also known in IR rulebooks as tangible authority to proceed, and strict rules govern how it is handled and passed on from one staff person to another.

The following are the most common types of tangible train working authorities in the block system. These are almost always issued on paper forms (except, of course, the block tokens). When these are issued in unusual circumstances (e.g., communications or signalling failure, floods, etc.) in sections where tokenless working is the norm, private numbers must be issued by the station masters concerned along with the paper authority. If communications between stations are disrupted the section controllers can issue paper authority with exchange of private numbers.

Block token (Neale's ball token, tablet token, electric staff token, or key token) Paper Line Clear ticket Starting Permit: Allows a driver to take his train on to a block section to begin its journey. Usually references a token number or paper line clear ticket. Authority to pass defective signal Authority to pass reception signal at On (to enter station limits) Authority to pass departure signal at On (to leave station limits) Authority to pass signal at On (gate, automatic, semi-automatic, or manual signal) Authority for train reception on unsignalled line Authority for train departure from unsignalled line Authority to proceed in Automatic Block section during prolonged failure of signals Authority to proceed without Line Clear Authority to proceed without Line Clear in Automatic Block territory Conditional Line Clear certificate (granting Line Clear following the reception of a train known to be en route) Caution Order (may enforce restrictions, or may cancel previous notices. A Reminder Caution Order reiterates a previous one.) Nil Caution Order (notice of absence of special restrictions until the next notice station) Guard's authority to work a part load from a section (in case of a train that has parted) Guard's permission to Driver to proceed with complete or partial train from mid-section to the next station Guard's permission to Driver to return to section from next station, when train has parted Authority to enter block section for shunting Shunting order when blocking forward Shunting order when blocking back Line Clear certificate for trolley / motor trolley / motor lorry Line Clear certificate (double line) for trolley / motor trolley / motor lorry Authority for trolley / motor trolley / motor lorry to enter block section without Line Clear certificate. In non-block systems of train working, the following kinds of authority to proceed are used:

Authority to Proceed, Following Trains system Pilot-guard Ticket Train-staff Train-staff Ticket Metal Token for One Train Only system

Source - IFRCA.org