1.3 Limited Clearances, Refuges & Trackside Structures

1.3 Limited Clearances, Refuges & Trackside Structures

The lineside is crowded with bridges, walls, signalling equipment, electrification masts and cable routes. On some parts of the railway the space between the track and the nearest wall or structure is very narrow. These are areas of limited clearance, and PTS holders must recognise them, understand the signs that mark them and know what they are allowed to do there. This topic is section 1.6 of the PTS handbook (RT3170) and section 10 of Rule Book Handbook 1.

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The Lineside Environment & Fixed Assets

As you walk along the cess or the ten-foot, you will meet a wide variety of equipment and structures:

1. Overbridges, underbridges, viaducts and tunnels: these often reduce the width of the cess to little or nothing, removing any place to stand clear of a train.
2. Retaining walls and cutting sides: a wall close to the track leaves no room to step aside when a train approaches.
3. Overhead line equipment (OLE) structures: masts and gantries carrying 25,000-volt equipment. They create pinch points, block sight lines and must be treated with the electrical rules in chapter 4.
4. Signalling apparatus and location cases: cabinets in the cess can force you closer to the line than you would otherwise walk.
5. Signals and signal gantries: tall signals, gantries over the tracks and small ground signals near the rails.

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Cable Troughing Routes

Signalling, power and telecommunications cables run alongside the track in cable troughing: concrete or plastic channels with removable lids. Troughing looks like a level path, but lids can be cracked, missing, loose or slippery, and a slip can throw you towards the line. Walk in the cess or on the authorised walking route your COSS identifies rather than on troughing lids, and report missing or broken lids as a close call.

          WHY TROUGHING LIDS ARE A POOR WALKING SURFACE
     +--------------------------------------------------------+
     | Cracked or brittle lids can break under your weight    |
     | Loose lids can tip when you step on the edge           |
     | Wet, icy or mossy lids are very slippery               |
     | A slip can throw you sideways towards the running line |
     +--------------------------------------------------------+

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Why Clearance Matters

A moving train is wider than the rails it runs on. Bodies sway on their suspension, loads and doors can project, and the air pressure around a fast train can unbalance you. That is why HB1 defines a position of safety as at least 1.25 metres (4 feet) from the nearest line on which a train can approach where the maximum speed is 100 mph or less, increasing to 2 metres (6 feet 6 inches) where the speed is over 100 mph. In an area of limited clearance you cannot achieve that distance on that side of the line.

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The Limited Clearance Signs in Handbook 1

HB1 section 10 shows three signs. Two designs are in use for the first two: an older board divided into coloured and white squares, and a newer white sign with a yellow warning triangle and a text panel.

   LIMITED CLEARANCE         NO REFUGES               PROHIBITION SIGN
  +---------+---------+    +---------+---------+    +---------------------+
  | WARNING |   RED   |    | WARNING |  BLUE   |    |  red circle, figure |
  +---------+---------+    +---------+---------+    |  crossed through    |
  |   RED   | Limited |    |  BLUE   |   No    |    |  "No safe access    |
  |         |clearance|    |         | refuges |    |  while trains are   |
  +---------+---------+    +---------+---------+    |  running"           |
  or a yellow warning      or a yellow warning      +---------------------+
  triangle sign with       triangle sign with
  "Limited clearance"      "No refuges"

1. Limited Clearance Warning Sign

• Appearance: a red-and-white board reading Warning – Limited clearance, or a white sign with a yellow warning triangle and the words Warning – Limited clearance.
• Meaning: there is no position of safety on this side of the railway for the length of the structure.
• Current wording: HB1 Issue 9 (in force from 6 December 2025) revised this section. It no longer says only that you must not be there "when a train is approaching", because the risk applies throughout the time any trains are running. The sign simply states what the location is: a place with no position of safety on that side.
• What you must do: the PTS handbook says there is no position of safety in an area of limited clearance; these are potentially dangerous places and you must not enter without the COSS first briefing you on the safe system of work through the area. The only exception is when carrying out emergency protection.

2. No Refuges Warning Sign

• Appearance: a blue-and-white board reading Warning – No refuges, or a white sign with a yellow warning triangle and the words Warning – No refuges.
• Meaning: there is no position of safety on this side of the railway for the length of the structure. However, there are positions of safety, or refuges, on the opposite side of the railway line.
• What you must do: plan with your COSS how you would reach the other side safely, because crossing open lines needs arrangements that the COSS has briefed.

3. Prohibition Sign

• Appearance: a red circle with a crossed-through walking figure and the words No safe access while trains are running.
• Meaning: you must not pass beyond this sign while trains are running, because you would not be able to reach a position of safety or refuge safely.
• Exception: you may pass it when you are carrying out emergency protection, and you must then take extreme care.

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Refuges and Tunnels

A refuge is a place where it is safe for you to stand when a train is passing. Refuges can be built out over an embankment or cut into the wall of a viaduct, cutting or tunnel.

• Keep refuges clear: a refuge is only useful if you can get into it. Never store materials or rubbish in one, and report any refuge that is blocked, damaged or overgrown.
• Using a refuge: get into it well before the train arrives, keep yourself and everything you are carrying inside it, and do not come out until the train has passed and you are sure no other train is approaching. When you are working under a warning system, stay there until the COSS tells you it is safe.
• Tunnels: tunnels can be very dangerous places and people are not allowed to work in most tunnels while trains are running. HB1 requires you to have a suitable lamp with you if you will be on or near the line in darkness or poor visibility, or if you are to enter a tunnel.

Telephones with Limited Clearance

Some railway telephones stand where there is limited clearance between the telephone and the adjacent lines. They are identified by a limited clearance sign on or near the telephone, or on the signal post or gantry. HB1 section 11 says you may use these telephones only in an emergency, and then only if no other form of communication is available.

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Actions When Approaching a Limited Clearance Area

Before you set off, the COSS should brief you on the walking route, any areas of limited clearance and any locations you must not go while trains are running. HB1 requires anyone going on or near the line alone to know the location of every area of limited clearance on the lines concerned.

• Stop and check: if you reach a limited clearance, no refuges or prohibition sign that was not covered in your briefing, stop and contact the COSS.
• Never "run the gauntlet": never hurry through a narrow bridge or tunnel hoping no train appears. A train at 90 mph covers about 40 metres every second.
• If a train approaches and you cannot reach a position of safety: the PTS handbook says lie down, but not in the four-foot, and gather loose clothing under you. This is a last resort; good planning means you should never be in that position.