Why is it important to choose the right crane rail size?
Sizing a crane rail is a highly critical engineering process that determines the exact rail profile, head width, and material grade required to safely support the dynamic loads of heavy lifting equipment. Incorrect sizing leads to catastrophic wheel wear, track deformation, and structural fatigue.
Common Crane Rail Profiles for Different Sizes：
- For Light Loads (Under 150 kN/wheel): Standard light rails (e.g., 22kg/m, 30kg/m) or ASCE profiles are often sufficient.
- For Medium Loads (150 kN - 300 kN/wheel): The European DIN 536 series (A65, A75) or the Chinese QU series (QU70, QU80) are standard choices, featuring a wide, flat base for stable mounting.
- For Heavy to Ultra-Heavy Loads (300 kN - 600+ kN/wheel): Massive profiles like the DIN A100, A120, A150, or QU100 and QU120 are required. These feature exceptionally thick webs and broad bases to distribute extreme localized pressures over the runway girder.
| RAIL TYPEPE | A (mm)A |
B (mm)B |
C (mm)C |
Weight (Kg/m) |
| RAIL A 45 | 45 | 55 | 125 | 22,1 |
| RAIL A 55 | 55 | 65 | 150 | 31,8 |
| RAIL A 65 | 65 | 75 | 175 | 43,1 |
| RAIL A 75 | 75 | 85 | 200 | 56,2 |
| RAIL A 100 | 100 | 95 | 200 | 74,3 |
| RAIL A 120 | 120 | 105 | 220 | 100 |
| RAIL GCR 108 | 2×610 | 100 | 263 | 107,9 |
| RAIL A150 | 150 | 150 | 220 | 150,3 |
| RAIL MRS 51 – CR 104 – 104 Ib ASCE | 63,5 | 127 | 127 | 51,59 |
| RAIL MRS 52 – CR 105 – 105 Ib ASCE | 65,1 | 131,8 | 131,8 | 52,09 |
| RAIL MRS 67 – CR 135 – 135 Ib ASCE | 76,2 | 146 | 131,8 | 66,97 |
| RAIL CR 73 | 100 | 135 | 140 | 73,3 |
| RAIL MRS 73 – AS 73 | 70 | 157 | 146 | 73,63 |
| RAIL MR 77 – 5 A | 100 | 100 | 200 | 77 |
| RAIL MRS 85 – CR 171 – 171 Ib ASCE | 101,6 | 152,4 | 152,4 | 84,83 |
| RAIL MRS 86 | 102 | 102 | 165 | 85,6 |
| RAIL MRS 87 A – PRI 85 R | 101,6 | 152,4 | 152,4 | 86,8 |
| RAIL MRS 87 B – CR 175 – 175 Ib ASCE | 102,4 | 152,4 | 152,4 | 86,8 |
| RAIL CR 100 | 120 | 150 | 155 | 100,2 |
| RAIL MRS 125 | 120 | 180 | 180 | 125 |
| RAIL MR 151 – PR 7 | 150 | 150 | 220 | 151,3 |
| RAIL MRS 221 | 220 | 160 | 220 | 221,4 |
| RAIL KP 70 – GOST: 4121-96 | 70 | 120 | 120 | 46,1 |
| RAIL KP 80 | 80 | 130 | 130 | 59,81 |
| RAIL KP 100 | 100 | 150 | 150 | 83,09 |
| RAIL KP 120 | 120 | 170 | 170 | 113,5 |
| RAIL KP 140 | 140 | 170 | 170 | 141,7 |
| RAIL ISCR 80 – IS:3443-80 | 80 | 130 | 130 | 64,2 |
| RAIL ISCR 100 | 100 | 150 | 150 | 89 |
| RAIL ISCR 120 | 120 | 170 | 170 | 118 |
| RAIL ISCR 140 | 140 | 170 | 170 | 147 |
| RAIL QU 70 – YB/T5055-93 | 70 | 120 | 120 | 52,8 |
| RAIL QU 80 | 80 | 130 | 130 | 63,7 |
| RAIL QU 100 | 100 | 150 | 150 | 89,1 |
| RAIL QU 120 | 120 | 170 | 170 | 118,1 |
| RAIL SP 120 | 120 | 170 | 170 | 118,28 |
The Core Principle of Sizing Crane Rail: Maximum Wheel Load
A common misconception when sizing a crane rail is relying solely on the crane's total lifting capacity (tonnage). In structural engineering, the rail size is dictated by the Maximum Wheel Load (often measured in kiloNewtons, kN). This is the absolute maximum downward force exerted by a single crane wheel when the crane is fully loaded and the trolley is positioned at the extreme end of the bridge, closest to the runway beam. Accurately calculating both the static wheel load and the dynamic impact factor is the foundational first step in selecting the correct rail profile.
Calculating the Required Rail Head Width
The physical width of the rail head is the most vital dimension when sizing a rail. The goal is to ensure that the contact stress (Hertzian pressure) between the curved crane wheel tread and the flat or slightly crowned rail head remains safely below the yield strength of the steel.
- If the rail head is too narrow, the concentrated pressure will cause plastic deformation (mushrooming) of the rail head and severely carve into the wheel flange.
- If the rail head is too wide, it increases the structural deadweight, wastes capital, and complicates the fastening system without providing any mechanical advantage.
- Engineering Rule of Thumb: The width of the rail head should generally be 10mm to 20mm narrower than the flat tread width of the crane wheel to allow for lateral movement and prevent the wheel flanges from binding against the sides of the rail.
GNEE RAILWAY RAILWAY are a primary manufacturer and a complete track system solutions provider. We deeply understand the mechanical relationship between crane wheels, rail profiles, and fastening structures. From helping you verify the optimal rail head width to manufacturing the exact heavy-duty profile with precision-cut custom lengths, and supplying the 100% compatible, micro-adjustable fastening components, we deliver an integrated, plug-and-play solution.
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