Railroad Rail Steel: Composition and Hardness Explained
Jan 22, 2026
What Metal Are Railroad Rails Made Of?
Railroad rails are made of high-carbon steel with controlled manganese and silicon, and optional microalloying elements such as chromium, vanadium and niobium. The composition is defined by standards: EN 13674-1 (Europe), AREMA (North America), JIS E 1101 (Japan) and GB/T 2585 (China). Carbon typically ranges from 0.60% to 0.82% and manganese from 0.7% to 1.4%.
Hardness of Common Rail Steels
| Grade | Standard / region | Typical composition (mass %) | Typical hardness |
|---|---|---|---|
| R260 | EN 13674-1 (Europe) | C 0.67-0.80, Mn 0.90-1.20, Si ≤ 0.50 | ≥ 200 HBW (specified minimum) |
| R350HT | EN 13674-1 (Europe) | C 0.75-0.85, Mn 0.80-1.20, Cr 0.20-0.50 | Head 350-400 HBW (minimum 350) |
| Grade 260 | AREMA (North America) | C ~0.77, Mn ~1.0-1.2, Si ~0.2 | ~250-300 HB typical |
| Grade 350 | AREMA + mill specs | C 0.78-0.83, Mn 0.90-1.20, Cr 0.2-0.6, + V/Nb | ~340-380 HB typical |
| BH rail (bainitic) | JIS E 1101; adopted in EU/India | C 0.65-0.80, Mn 1.0-1.4, Cr/Mo/Ni optional | Head ~370-400 HB |
| U71Mn | GB/T 2585 (China) | C 0.65-0.77, Mn 1.10-1.40, Si 0.15-0.35 | 240-270 HB |
| U75V | GB/T 2585 (China) | C 0.67-0.77, Mn 0.70-1.00, V 0.04-0.12 | ~280-320 HB typical (heat-treated) |
How Hard Is Rail Steel?
Standard carbon rails (R260, Grade 260, U71Mn) measure about 240-300 HB. Head-hardened or heat-treated grades (R350HT, Grade 350, BH rail) achieve head hardness around 340-400 HB, providing longer service life on curves and high-tonnage lines. Hardness is verified by Brinell (HB/HBW) or Rockwell methods per the governing standard.
Why Hardness Matters
Harder rail head steel wears more slowly. On sharp curves and heavy-haul lines, the difference between 260 HB and 380 HB rail head hardness can mean 30-50% longer life before grinding or replacement. The trade-off is higher cost and more demanding welding and grinding, so hardness is specified to match the traffic.
Common Rail Sizes and Profiles
In practical purchasing, buyers focus on standardized rail profiles that match existing track systems: light rail (8-30 kg/m), heavy rail (38-60 kg/m), crane rail QU70-QU120 and DIN 536-1 A55-A120, and UIC 860 profiles such as 33, 46, 54 and 60 kg/m. Confirm the exact profile dimensions and weight for the required type with the governing standard before ordering.
Frequently Asked Questions
What metal are railroad rails made of?
High-carbon steel with controlled manganese, silicon and optional microalloying (chromium, vanadium, niobium), per standards such as EN 13674-1, AREMA, JIS E 1101 and GB/T 2585.
How hard is rail steel?
Standard carbon rail is about 240-300 HB; heat-treated grades such as R350HT reach 350-400 HBW at the rail head for longer wear life.
What is the difference between R260 and R350HT?
R260 is standard carbon rail; R350HT is head-hardened with a minimum head hardness of 350 HBW and a minimum tensile strength of 1100 MPa, preferred on curves and high-tonnage lines.
How is rail hardness measured?
By Brinell (HB or HBW) indentation on the rail head, or Rockwell for hardened rails, following the method in the governing standard.
Does harder rail cost more?
Yes, head-hardened rail costs more per tonne, but longer wear life on curves usually lowers total lifecycle cost on heavy-traffic lines.
What hardness is U71Mn rail?
U71Mn rail is typically delivered at 240-270 HB, matching its carbon-manganese composition; it work-hardens further in service under wheel loads.
