What is the anchor length in a railway track?
Jan 04, 2026
What is the anchor length in a railway track?
In a railway track, "anchor length" refers to the required length of rail section that needs to be fixed to resist forces (thermal expansion/contraction or vibration) before an expansion joint or specific anchor point, often spanning at least two rail lengths (e.g., 39-78 ft or more) where every third tie might be strongly anchored (box-anchored) to secure the track. It's the zone where rail movement is prevented, ensuring stability, especially near bridges or where long welded rails meet jointed sections, allowing the rest of the track to "breathe".
Key Aspects of Anchor Length:
- Purpose: To stop longitudinal (along the track) movement in sections of track that might otherwise shift due to temperature changes or train vibrations.
- Location: Commonly used approaching open-deck bridges, at the ends of Long Welded Rails (LWRs) before switch expansion joints (SEJs), or where track design requires fixation.
- Implementation: Often involves applying anchors (spring steel clips) to the rail base and pressing against the sleeper (tie).
- Variable Length: The specific length depends on the rail type, temperature variations, track gradient, and the specific engineering requirements of the railway system, varying from tens to hundreds of meters.
What is the function of a rail anchor?
A rail anchor's main function is to prevent the rail from moving longitudinally (sliding forward or backward) along the crossties, a phenomenon called "creeping," caused by temperature changes and train traffic. By clamping onto the rail base and pressing against the tie, these spring-steel devices transmit forces, maintain rail alignment, and prevent wear on wooden ties, ensuring track stability and safety, especially on curves, gradients, and high-speed lines.
| Type |
Used in 50Kg, 85Kg,90/91LB, 115RE /136RE ,UIC54 & UIC60 rail, or other types upon customers' drawings. |
||
| Material | 60Si2MnA | 45# | QT500-7 |
| Chemical composition(%) |
C:0.56-0.64, Mn:0.60-0.90, Si:1.60-2.00, Cr:≤0.35, P:≤0.03, S:≤0.03
|
C:0.42-0.50, Mn:0.50-0.80, Si:0.17-0.37, Cr:≤0.25, P:≤0.035, S:≤0.035 |
C:3.60-3.80, Mn:≤0.6, Si:2.50-2.90, P:≤0.08, S:≤0.025 |
| Surface | plain (oiled),color painting, zinc painted or HDG | ||
| Standard | AS1085.10-20002 , DIN, ISO-9001 | ||
Where are rail anchors used?
- The railway anchor is used in some parts of the railway. Take a 39-foot track for example, it requires evaluation of 8 rail anchors, as shown in the following figure. With the increase of slope, it needs more amount of rail anchors.
- The rail anchoring device is applied in the track near the open deck bridge, one third of the joints are intended to be fixed at the ends of the bridge for at least 2 rail length.
- As a railroad track with an anchor, each third strip should be box anchored, with at least two rail lengths from the intersection to all directions.
- Rail anchors can be used for railway turnouts. It is helpful to correct geometric problems when using anchors in turnouts.
GNEE RAIL supplies rail anchors that fit various rail section dimensions such as 85LB, 90LB, 115RE, 132RE UIC54, UIC60, 50kg, etc. The products are manufactured based on high standards and have passed the ISO9001 certificate, proving to compete in different conditions.
