Track centreline distance
In railways the track centreline distance is the horizontal distance between the axes of adjacent tracks (track centres).
Distance between main lines:
The minimum distance between two tracks is 3.50 m. This figure comes from the history of the railways. The previously defined half vehicle gauge was 1575 mm. If vehicles are standing on two parallel tracks laid at a distance of 3.50 m apart there remains a dimension of 350 mm between the loading gauges for protection and operating conditions. This intermediate space was sufficient for safe operation at low speeds and with hard wagon suspensions.
The current minimum distance between tracks in accordance with EBO is determined by adding half the width of the relevant loading gauges. The standard normal distances apart of tracks on the main line with radii r = ≥ 250 m are listed in one of the following tables.
Description of the track system
Extensive track renewal and track laying
S – Bahn (Ve ≤ 120 km/h)
- underground shelter adjacent to the tracks
- underground, shelter between the tracks
Upgraded lines (Ve ≤ 230 km/h)
Ve≤ 300 km/h
Ve ≤ 200 km/h
Two-way working - signals between the tracks
Between track pair
Radius increase with a radius ≤ 250 m
Distance between tracks in stations:
The distance between tracks in stations shall be at least 4.50 m. If there are considerable extra costs in providing this distance apart direct lines through the station may have the same distance apart as the main lines. Some important track distances apart are shown in the next table.
Description of the track system
Minimum distance apart for new tracks
Signals between the tracks
Shunting paths between the tracks
It should be noted that in case of electric traction the space required for the catenary masts must be kept free. As a rule, individual support points are provided; thus, there are no masts between the tracks in double-tracked lines.
Track spacing for tracks with superelevation:
The track spacing e is measured as the distance apart of the track centres (track axis) parallel to the rail heads concerned. The surveying of the distance apart of the tracks refers to the horizontal distance e h. In tangent track, where the rails are laid without superelevation, track spacing and peg out dimension are identical. If the axes of the tracks in the curve are at the same height then the peg out dimension e h is greater than the distance between the tracks e, if the axes are on an inclined plane, the peg out dimension e h is smaller than the distance between the tracks e.
Distances to engineering structures:
The horizontal distance between the track axis and engineering structures (e.g. bridge structures, support and noise protection walls) is determined by the danger zone and the safety space. The danger zone for ≤ 160 km/h is 2.50 m and for 160 ≤ v ≤ 300 km/h, 3.00 m. These distances apply to a superelevation of u = 20 mm. For larger superelevations the distances should be increased and this increase can be calculated. The safety space is a uniform 0.80 m and should be kept free up to a height of 2.20 m.
The space to be kept clear under overhead structures is determined by the clearance height and the width. The clear height refers to the distance between the top of the rails and bottom edge of the building ceiling.
The distance from
Minimum clear width
V ≤ 160 km/h
160 ≤ v ≤ 200 km/h
200 ≤ v ≤ 300 km/h