Steel Rail

Railway rail and crane rail are both asymmetric I-section steel profiles designed to guide and support wheeled vehicles, but they differ significantly in cross-section geometry, designation system, and load characteristics to suit their respective applications. Railway rail (Vignole rail) is designated by linear weight in kg/m (43, 50, 60, 75 kg/m) and features a relatively narrow, rounded mushroom-shaped head optimised for the conical tread profile of railway wheel flanges, a slender web providing sufficient height for bending resistance, and a broad flat base for fastening to timber or concrete sleepers with rail clips, spikes, or baseplate systems. The rounded head profile allows the wheel contact point to shift laterally across the head width as the wheelset steers through curves, distributing rolling contact fatigue damage across the full head width rather than concentrating it at a single point. Crane rail (DIN A-series or GB QU-series) is designated by head width in millimetres (A45, A75, A100, A120, A150; QU70, QU80, QU100, QU120) and features a wider, flat-topped head providing a large contact area for the flat or slightly convex tread of crane wheels, a much heavier web and base section to resist the concentrated static and dynamic wheel loads of overhead cranes (which can reach 500–1,000 kN per wheel for large ladle cranes), and a flat base for bolted attachment to crane runway beams using rail clamps, fishplates, or welded rail seats. Crane rails are not interchangeable with railway rails — using railway rail as crane rail risks premature head wear, head checking, and lateral instability of the crane wheel due to the rounded head profile mismatch with flat crane wheel treads. Selection should be based on: application type (railway track vs. crane runway), wheel load, crane capacity and wheel base, running speed, and applicable design standard (EN 13674 for railway; DIN 536 / GB/T 11264 for crane rail).

R260, R350HT, and R400HT are rail steel grades defined in EN 13674-1 (European standard for flat-bottom railway rail), differentiated primarily by rail head hardness and tensile strength, which determine wear resistance and rolling contact fatigue life in service. R260 (minimum tensile strength 880 MPa, head hardness 260–300 HBW) is the standard pearlitic carbon rail grade produced by as-rolled cooling without post-rolling heat treatment. It provides adequate wear resistance for moderate-traffic mainline freight and passenger railways, light industrial railways, and crane runway applications. R260 is the most widely used and most economical rail grade globally, suitable for straight track and gentle curves on lines with axle loads up to approximately 25 tonnes and traffic density up to 25 MGT (million gross tonnes) per year. R350HT (minimum tensile strength 1,175 MPa, head hardness 350–390 HBW) is a head-hardened rail produced by accelerated quenching of the rail head from rolling heat or after reheating, creating a fine pearlitic microstructure with significantly higher hardness than as-rolled R260. R350HT provides 2–3× longer service life than R260 in curved track (radius below 800m), high-axle-load heavy haul freight applications (30–40 tonne axle loads), and high-traffic-density routes where rail grinding intervals are extended. It is specified for curve rails, transition zones, switch and crossing stock rails, and crane rails in high-cycle industrial applications. R400HT (minimum tensile strength 1,280 MPa, head hardness 400–440 HBW) is the premium head-hardened chromium-vanadium alloyed grade providing maximum wear resistance for the most demanding applications including very sharp curves (radius below 400m), heavy haul coal and iron ore railways with 32–40 tonne axle loads, high-speed line switch and crossing rails, and steelmaking ladle crane runways subject to extreme thermal and mechanical cycling. Grade selection should be based on track curvature, design axle load, annual traffic tonnage, rail grinding programme, and life-cycle cost analysis comparing material premium against extended rail replacement intervals.

Steel rails are supplied from the mill in standard discrete lengths of 12m (most common for crane rail and industrial track), 18m (standard railway rail length for jointed track in many countries), and 25m (the standard mill length for most modern mainline railway supply in Europe, China, and Australia). Some mills produce 50m long rails for direct delivery to flash butt welding plants. Continuous Welded Rail (CWR) is the modern standard for high-speed, heavy haul, and mainline railway track construction, produced by flash butt welding individual mill-length rails end-to-end at a rail welding plant to produce long strings typically 150–500m in length. These welded strings are transported to site on rail wagons or road vehicles and laid directly on prepared sleepers, eliminating the conventional rail joints (fishplated joints) between individual rail lengths. CWR provides major advantages over jointed track: elimination of the impact loading spike at rail joints that causes sleeper damage, ballast deterioration, and rail end batter; significantly smoother ride quality for passengers; lower track maintenance costs; reduced noise and vibration; and higher permissible train speeds. CWR must be installed within a defined temperature range (neutral temperature or stress-free temperature, typically 25–35°C for temperate climates) and anchored with sufficient rail fastening resistance to prevent thermal buckling (sun kinking) in summer heat and rail breakage in winter cold. Flash butt welding of individual rail lengths is also performed on site using mobile flash butt welding machines to close gaps between pre-laid strings. Aluminothermic (thermite) welding is used for site closure welds and repairs. We supply standard mill-length rails (12m, 18m, 25m) and can coordinate flash butt welding services for CWR string production to project requirements.

UIC 60 (also designated 60E1 per EN 13674-1, or 60 kg/m in Chinese and Japanese standards) is the standard flat-bottom railway rail profile developed and standardised by the International Union of Railways (UIC) with a nominal linear weight of 60.34 kg/m. Its principal dimensions are: total height 172mm, head width 72mm, base width 150mm, web thickness 16.5mm, and head height 51.5mm. UIC 60 has become the dominant mainline railway rail profile worldwide for several reasons: (1) Structural efficiency — the 172mm section height provides excellent bending resistance and section modulus for the 60 kg/m weight, efficiently distributing wheel loads over multiple sleepers and minimising bending stress in the rail web and base. (2) Head geometry — the 72mm head width and carefully profiled head radius are matched to the standard conical wheel tread profile (1:20 or 1:40 taper depending on system) providing optimal contact mechanics, minimising contact stress, and accommodating the range of wheel-rail contact positions encountered through curves. (3) International standardisation — UIC 860 and EN 13674-1 specifications for UIC 60 / 60E1 are accepted by railway authorities across Europe, the Middle East, North Africa, Southeast Asia, and Australia, enabling standardised procurement and rail supply logistics across multiple national networks. (4) Axle load capacity — UIC 60 in R260 grade supports axle loads up to 22.5 tonnes for passenger service and 25 tonnes for freight per UIC loading standards; R350HT grade extends this to 30+ tonnes for heavy haul applications. (5) Supply availability — UIC 60 / 60E1 is the highest-volume production rail profile at most major rail mills worldwide, ensuring competitive pricing, short lead times, and reliable global availability. For projects specifying non-UIC rail profiles (50 kg/m industrial, 75 kg/m heavy haul, AREMA 136RE for American projects), equivalent structural performance can be verified against UIC 60 as the reference section.

Crane rail selection for an overhead travelling crane runway involves matching the rail profile to the crane wheel load, wheel diameter, wheel type, and crane runway beam configuration. The key design parameters are: (1) Maximum wheel load — the heaviest wheel load in the crane's loaded condition, calculated from crane capacity, lifting height, bridge span, end carriage geometry, and dynamic load factors per FEM 1.001 or CMAA 70/74. Typical maximum wheel loads range from 50–150 kN for light workshop cranes to 500–1,000 kN for heavy steelmaking ladle cranes. (2) Wheel diameter and tread width — larger wheel diameters distribute load over a longer rail contact length, reducing contact stress. Crane wheel treads are typically flat or have a slight crown radius, and the rail head width must be matched to the wheel tread width to prevent wheel edge riding on the rail head crown. (3) Contact stress verification — the Hertzian contact stress at the wheel-rail interface must be limited to prevent rail head deformation, plastic flow, and spalling. DIN 536 provides tables of maximum wheel loads for each A-series crane rail profile based on crane wheel diameter and wheel type (cylindrical flat tread vs. flanged). (4) Rail height and base width — sufficient rail height provides bending resistance and web buckling resistance; sufficient base width ensures stable bearing on the crane runway beam top flange and adequate width for rail clamp attachment. General selection guidance: DIN A45/A55 (head width 45–55mm) for cranes up to 10 tons capacity, wheel load up to 80 kN; DIN A65/A75 for 10–32 tons, wheel load 80–160 kN; DIN A100 for 32–100 tons, wheel load 160–320 kN; DIN A120/A150 or QU100/QU120 for over 100 tons heavy industrial cranes, wheel load 320–800 kN. Rail fastening system — rail clamps, bolted fish plates, or continuous welded attachment — must also be specified to ensure rail stability under lateral crane wheel forces and prevent rail creep under repeated thermal and mechanical cycling.