Railway Rails: Flat-Bottom, Bullhead and Double-Headed Rails, Profiles and Grades

Quick Answer

A railway rail has three parts: the head that carries the wheel, the web, and the foot that sits on the sleeper. Flat-bottom (Vignoles) rail has a wide foot fastened straight to the sleeper or a baseplate with spikes, screws or clips, and is the standard rail for new track worldwide. Bullhead rail has a head larger than its foot and sits in cast-iron chairs, held by wedges called keys; it was Britain's standard rail until the mid-20th century and now survives mainly on heritage lines and older track. Double-headed rail had an identical head and foot so it could be turned over when worn, but the chairs often dented the lower head. Modern rail is ordered by profile and steel grade. EN 13674-1 covers Vignole rails of 46 kg/m and above: 60E1 (formerly UIC 60) weighs 60.21 kg/m, 54E1 (UIC 54) 54.77 kg/m and 49E1 49.39 kg/m. North American sections such as 115RE and 136RE are named by weight in lb/yd. EN grades run from R200 to R400HT: R260 rail has a running-surface hardness of 260–300 HBW, and heat-treated grades such as R350HT (350–390 HBW) go where wear is severe. One kilometre of single track in 60E1 takes 120.42 t of rail.

A typical rail enquiry reads: "Rails, 60 kg, 5 km, best price." It looks complete, but it isn't. "60 kg" could mean 60E1, 60E2, a Chinese GB 60 kg/m rail or another national section, and fastenings, fishplates and weld moulds must be matched to the exact profile. The enquiry gives no steel grade, no standard and no lengths, and says nothing about fastenings or welding.

Rail is bought by profile, grade and length, each chosen for the track it goes into. This guide explains the rail types, how profiles are named, what the grades mean and what a complete order contains.

Rail Anatomy: Head, Web and Foot

Every rail has three parts:

• Head — profiled to carry the wheel and resist wear; its top is the running surface, and its inner side, which guides the wheel flange, is the gauge face
• Web — the vertical middle section that carries load from the head down to the foot
• Foot (or base) — the bottom, shaped to suit the fixing: a wide, flat foot on flat-bottom rail, a smaller bulb on bullhead rail

A rail works as a continuous beam on the sleepers, and its bending stiffness spreads each wheel load over more of them. Stiffness rises faster than weight: 60E1 is about 10% heavier than 54E1 but, at 172 mm tall against 159 mm, has about 30% more vertical moment of inertia (3,038 against 2,338 cm⁴). Heavier sections therefore go into high-speed and heavy-haul track.

Flat-Bottom, Bullhead and Double-Headed Rails

Flat-bottom (Vignoles) rail

Flat-bottom rail has a wide foot that rests on the sleeper or a steel baseplate, held down by spikes, screws or elastic clips. The first 500 flat-bottom rails reached Philadelphia in 1831 for Robert Stevens of the Camden and Amboy Railroad; in Britain the engineer Charles Vignoles recommended the design to the London and Croydon Railway in 1836, hence the name Vignoles rail. It is now the dominant rail profile worldwide.

Early flat-bottom rail was spiked straight to timber sleepers, where the foot cut into the wood and the spikes worked loose. Baseplates (tie plates) reduced this by spreading the load.

Double-headed rail

Early British main lines such as the London and Birmingham Railway used double-headed rail, with an identical head and foot, seated in cast-iron chairs. A worn rail was meant to be turned over. In 1835 the engineer Peter Barlow warned that the chairs would dent the lower head; some railways found exactly that, though others did turn their rails.

Bullhead rail

Bullhead rail grew out of the double-headed rail. Its head is larger than its foot, putting extra metal where the wear happens, so it cannot be reversed. It sits in heavy cast-iron chairs, held by wooden and later steel keys that need regular checking. Bullhead was Britain's standard rail from the mid-19th to the mid-20th century (BS 9 was first published in 1905), and the changeover was slow: in 1954 it was still laid on 723 km (449 miles) of new track, against 1,485 km (923 miles) of flat-bottom.

Bullhead survives on heritage railways, some older branch lines and sidings, and parts of the London Underground.

Why flat-bottom won

The wide foot spreads load onto the sleeper without a chair and gives the rail far more lateral stiffness. The 39E1 flat-bottom rail weighs 39.77 kg/m, about 16% less than the 95 lb bullhead, yet has about 28% more lateral moment of inertia (219.6 against 171 cm⁴). Flat-bottom track also needs fewer parts per sleeper: no chair and no key to inspect, tighten or replace.

Rail Profiles and How They Are Named

EN 13674 profiles

In Europe, EN 13674-1 covers Vignole (flat-bottom) rails of 46 kg/m and above for conventional and high-speed track. The 2011 edition, as amended in 2017, specifies 23 profiles and nine pearlitic steel grades, with two classes of straightness and two of profile tolerance; check the edition your contract cites. EN 13674-4 covers lighter Vignole rails from 27 kg/m up to, but not including, 46 kg/m.

A profile name gives the approximate mass in kg/m, the letter E and a variant number, so 60E1 and 60E2 are two different 60 kg/m profiles. Many profiles also carry an older name: 60E1 was UIC 60, 54E1 was UIC 54, 56E1 the British 113 lb section and 49E1 the S49.

Section data from a European rail maker's published tables; 49E1 from published supplier data. A later version of 136RE weighs 67.76 kg/m. lb/yd = kg/m × 2.0159.

Other national families

• North America (AREMA): sections are named by nominal weight in lb/yd with the suffix RE, such as 115RE and 136RE
• China: GB/T 2585 covers hot-rolled and on-line heat-treated rails from 38 to 75 kg/m, with fixed lengths of 12.5 and 25 m for 38 and 43 kg/m rail; 12.5, 25 and 100 m for 50 and 60 kg/m; and 25, 75 and 100 m for 75 kg/m
• Former Soviet Union: 65 kg/m rail is the common heavy section, with 75 kg/m also used

Sections of similar mass from different families are not interchangeable: their dimensions differ, and fastenings, fishplates and weld moulds fit one profile.

Rail Steel Grades

EN 13674-1 specifies nine pearlitic steel grades with running-surface hardness from 200 to 440 HBW, heat-treated and non-heat-treated, alloy and non-alloy. Harder rail wears more slowly, which matters on curves, where wheel flanges grind the gauge face, and under heavy axle loads.

The standard's other two grades are R320Cr and R370CrHT; take their properties from the current edition. Older specifications still cite UIC 860 grades: grade 700 (680–830 MPa tensile strength) and grades 900A and 900B (880–1,030 MPa), whose minimum matches R260's 880 MPa.

Grade choice is the track engineer's decision, based on curvature, tonnage and the railway's standards: standard grades suit most track, and heat-treated grades go on tight curves, heavy-haul lines and other high-wear locations.

Crane Rails and Light Rails

Crane runways use a different family. DIN 536 Part 1 A-series crane rails are squat sections with a foot wider than they are tall, made to be clamped or bolted to a runway girder. The number in the name is the head width in millimetres:

Light railway rails, from 27 kg/m up to 46 kg/m, fall under EN 13674-4; 39E1 (formerly BS 80A) is one. In North American practice, sections under about 100 lb/yd (49.6 kg/m) usually serve lighter freight, low-use track or light rail.

Fastenings: From Chairs and Keys to Clips and Stud Bolts

• Chairs and keys — cast-iron chairs fixed to the sleeper, with bullhead or double-headed rail wedged in by wooden or steel keys
• Baseplates (tie plates) — steel plates under flat-bottom rail that spread the load into the sleeper
• Rail pads — resilient pads under the rail that reduce vibration
• Spikes, screws and elastic clips — hold the foot down; elastic clips keep their clamping force under vibration
• Fishplates (joint bars) and fish bolts — join rail ends in jointed track and at insulated joints
• Stud bolts — headless threaded fasteners with a nut at each end that fix rails, baseplates and sleepers to supporting structures, including crane and industrial rail installations

Fastening systems are designed around one profile, so a change of rail profile usually means new fastenings. For general bolting practice, see our guide to industrial fasteners and stud bolts.

Welding Rails: Flash-Butt and Aluminothermic

Most main lines now run on continuous welded rail (CWR). Two processes make the joints:

• Flash-butt welding — the rail ends are clamped, heated by electric current and arcing (flashing), forged together and trimmed. It is mostly done in fixed plants that weld mill lengths into long strings, covered by EN 14587-1 for new EN 13674-1 rails in grades R220 to R400HT; mobile machines also weld on site
• Aluminothermic (thermite) welding — aluminium powder and iron oxide react in a crucible above a mould clamped round the rail gap, and the molten steel fills the gap. It needs little equipment, so it is the usual method for welds in track. EN 14730-1 covers process approval; EN 14730-2 covers welder qualification, contractor approval and acceptance of welds

An approved thermite process applies to new rails of the same profile and steel grade. Joining 54E1 to 60E1, worn rail to new, or one grade to another falls outside that approval and needs its own qualified solution.

Continuous Welded Rail and Thermal Force

A rail that is free to move grows by α × L × ΔT. With α = 1.15 × 10⁻⁵ per °C, a free 25 m rail warming by 30 °C lengthens by about 8.6 mm, which is why jointed track leaves expansion gaps at the fishplates. Welded rail is held by its fastenings and the ballast and cannot move, so the same temperature change becomes stress: σ = E × α × ΔT.

Worked example: thermal force in a 60E1 rail

• Cross-section: 60.21 kg/m ÷ 7,850 kg/m³ = 76.7 cm² (7,670 mm²)
• Stress per °C: 207,000 MPa × 1.15 × 10⁻⁵ = 2.38 MPa
• Force per °C: 2.38 MPa × 7,670 mm² = 18.3 kN per rail
• Hot day: rail stress-free at 27 °C and heated to 57 °C (ΔT = 30 °C) carries about 71 MPa, or 548 kN of compression per rail: about 1,096 kN, roughly 112 tonnes-force, per track
• Unrestrained: a 1 km length would try to grow 345 mm

Hot weather pushes welded track toward buckling and cold weather toward pull-aparts, so railways fix the rail at a chosen neutral (stress-free) temperature. Britain uses 27 °C; hot-climate railways set it higher, and one Australian study reports 48 °C. It is set by the railway's track standards, not the rail supplier.

Worked Example: How Much Rail Does a Line Need?

A 12 km single-track industrial line in 60E1:

• Rail mass: 2 rails × 12,000 m × 60.21 kg/m = 1,445 t
• In 25 m lengths: 960 rails of about 1.51 t each
• Field welds to make it continuous: 2 × (480 − 1) = 958 with 25 m rails, but only 2 × (120 − 1) = 238 if the mill supplies 100 m rails and the site can handle them
• The same line in 49E1: 2 × 12,000 × 49.39 = 1,185 t, about 260 t less steel, for a less stiff track

Add the buyer's own allowance for closures, cutting and spares (2% takes the 60E1 figure to about 1,474 t). Turnouts and insulated joints are ordered as separate items.

Ordering Checklist

• Profile and standard: for example 60E1 to EN 13674-1, 115RE to AREMA or 60 kg/m to GB/T 2585, or a drawing; for extensions, the profile already in track
• Steel grade: R260, R350HT or the national equivalent
• Quantity: tonnes and metres
• Lengths: fixed lengths or long rails, end condition (drilled for fishplates or plain for welding) and length tolerance
• Tolerances: straightness and profile tolerance class; EN 13674-1 has two of each
• Fastenings and joints: baseplates, pads, clips, screws or stud bolts, fishplates and fish bolts, matched to the profile
• Welding: thermite portions and moulds for the exact profile and grade, or flash-butt welding into strings
• Documents: mill certificates to EN 10204 3.1 or 3.2 with chemistry and hardness, plus acceptance test and inspection records; see our guide to material test certificates
• Delivery: maximum transportable length, handling, port of discharge and marking

Common Mistakes

1. Ordering "60 kg rail" without a designation. 60E1, 60E2 and the GB 60 kg/m rail are different profiles: 60E1 and 60E2 differ in the head, and the GB rail is a different section, so fishplates, weld moulds and fastenings must be checked against the exact profile.

   Prevention: Name the profile and its standard; for extensions, check the profile already in track.

2. Using a thermite process outside its approval. A process approved for one profile and grade does not cover a different section, worn rail or another grade.

   Prevention: Order weld kits for the exact profile and grade combination, and qualify a procedure for anything else.

3. Soft rail where wear is severe. Standard-hardness rail on tight curves or heavy-haul lines wears fast on the gauge face and has to be renewed early.

   Prevention: Specify heat-treated grades where the track engineer's assessment calls for them.

4. Treating bullhead and flat-bottom rail as interchangeable. Bullhead needs chairs and keys, and a flat-bottom foot will not seat in a bullhead chair.

   Prevention: For chaired track, order bullhead rail with matching chairs and keys, or plan a proper transition.

5. Forgetting fastenings and joints. The rail arrives on site, the clips and fishplates do not, and track laying stops.

   Prevention: Order fastenings, pads, fishplates and bolts with the rail, matched to the profile.

6. Laying welded rail without a neutral temperature plan. Rail fastened on a cold day without stressing carries high compression in summer and can buckle.

   Prevention: Follow the railway's stress-free temperature rules when fastening, stressing and destressing.

7. Accepting rail without certificates. Chemistry, hardness and inspection records are the only proof of grade.

   Prevention: Require mill certificates and check them against the order before the rail is laid.

Supply from Kasko Makine

Kasko Makine supplies railway rails and rail stud bolts:

• Flat-footed rails — flat-bottom (Vignoles) rails that sit directly on sleepers, used with steel bearing plates, for main lines, freight and passenger networks, high-load and long-distance routes and standard railway infrastructure projects
• Bull-headed rails — traditional rails with a head thicker than the foot, seated in chairs and secured with keys, for traditional track, heritage and preserved lines and older networks
• Double-headed rails — symmetrical rails with identical head and foot, seated in chairs and secured with keys, for early railway track, heritage and preserved railways and historical rail infrastructure
• Rail stud bolts — headless threaded fasteners secured with nuts at both ends, in high-grade carbon or alloy steel with optional galvanising or anti-corrosion coatings, for fixing rails, base plates and sleepers in railway track construction, rail fastening and anchoring systems, and industrial and crane rail installations, supplied for use with the rails within the same project scope

Engineering support: Send the profile, steel grade, standard, lengths and quantity, or a drawing or sample of the rail already in track. We will check the profile, grade and fastenings against your data and quote rails and stud bolts together.

Send the rail profile, steel grade, standard, lengths and quantity for a quotation — we reply within 24 hours. Reach us at info@kaskomakine.com or WhatsApp +90 (537) 521 1399.

Continue Reading

• Shear Stud Connectors: Specifications, Design Resistance and Stud Welding
• Industrial Fasteners: Stud Bolts, Hex Bolts, Nuts and Washers
• Anchor Bolts: Types, Specifications and Applications
• Material Test Certificates: EN 10204 3.1 vs 3.2
• Plant Construction and Erection Equipment
• Material Handling: Conveyors and Bucket Elevators

Frequently Asked Questions

Q: What is the difference between flat-bottom and bullhead rail?
A: Flat-bottom rail, also called Vignoles rail, has a wide flat foot fastened directly to the sleeper or a baseplate with spikes, screws or clips. Bullhead rail has a head larger than its foot and sits in cast-iron chairs, held by wooden or steel keys. Flat-bottom rail is stiffer sideways and needs fewer parts, so it became the world standard; bullhead survives mainly on heritage and older track.

Q: What does 60E1 mean in rail profiles?
A: 60E1 is a flat-bottom rail profile in the European standard EN 13674-1. The number gives the approximate mass, 60 kg per metre (exactly 60.21 kg/m), and the final digit identifies the variant, so 60E2 is a different 60 kg/m profile. 60E1 was formerly called UIC 60. It is 172 mm tall with a 150 mm foot, and its fastenings, fishplates and weld moulds must be ordered for the same profile.

Q: How much does railway rail weigh per metre?
A: It depends on the profile. Common EN 13674 profiles weigh 49.39 kg/m (49E1), 54.77 kg/m (54E1) and 60.21 kg/m (60E1). North American 115RE weighs about 56.8 kg/m and 136RE about 67.5 kg/m. Because track has two rails, one kilometre of single track needs twice the mass per metre in tonnes: 120.42 tonnes of rail for 60E1, or 98.78 tonnes for 49E1.

Q: What are R260 and R350HT rail steel grades?
A: They are steel grades in EN 13674-1, which specifies nine pearlitic grades from 200 to 440 HBW. R260 is a carbon-manganese grade with a running-surface hardness of 260 to 300 HBW and a minimum tensile strength of 880 MPa. R350HT is heat-treated to 350 to 390 HBW for better wear resistance and is used where wear is severe, such as on tight curves and heavy-haul track.

Q: Why was double-headed rail abandoned?
A: Double-headed rail had an identical head and foot so that a worn rail could be turned over and used again. In practice the cast-iron chairs often dented the lower head, so after turning, the new running surface was already damaged; the engineer Peter Barlow predicted this in 1835. Railways moved to bullhead rail, which puts more metal in the head, and then to flat-bottom rail, which needs no chairs.

Q: How are railway rails welded?
A: Two processes are used. Flash-butt welding clamps the rail ends, heats them with electric current and forges them together, mainly in fixed plants that weld rails into long strings under EN 14587-1. Aluminothermic or thermite welding fills a mould around the rail gap with molten steel from a crucible reaction and is used in track; its processes are approved under EN 14730-1 for rails of the same profile and grade.

Q: What are crane rails and how do they differ from railway rails?
A: Crane rails carry the wheels of overhead and gantry cranes on runway girders. The common European family is the DIN 536 A-series: squat sections with a very wide foot for clamping or bolting down, named by head width. An A75 rail has a 75 mm head, stands 85 mm high, has a 200 mm foot and weighs 56.2 kg/m. Railway rails are taller and slimmer because they span between sleepers.