Types of rail

Railway rails come in many types and a multitude of varieties. I’ll briefly try to explain some of the more commonly found ones.

This article is part of my series exploring some of the basics of rail. If you'd like to see more then follow #rail101 and/or me.

Vignoles / Flat bottomed rails

This type of rail is the most common type of railway rails you’ll find and there are many different shapes and sizes of them but they share a few common features. They are symmetrical (vertically) and they have a flat base to enable them to sit on pads/sleepers. Charles Blacker Vignoles is credited with the invention of these flat bottomed rails and so they bear his name to this day.

Grooved rails

Grooved rails as their name implies, have a groove in them. This deep and wide groove is used to provide flangeway clearance for railway wheels. They are typically laid into road or grass areas and the "keeper" part of the rail stops the road surface fouling the space needed for tramway wheel flanges to pass.

Check rails

These are a rail which the train does not run on top of it, rather the back of the wheels rub against them in areas where extra steering forces for the axles may be needed, such as very sharp curves or to provide additional safety in switch and crossing layouts. They restrain the flat back of the wheel to direct it around sharp curves or to the correct route set at switches and crossings. Various rails can be used as check rails – even normal flat bottomed rails in some circumstances, however generally the most common check rail section used today is 33C1 with virtually identical equivalents U69 and UIC33.

N.B. North American railways can call these Guard rails, but that has a very different meaning in UK/Europe

Guard rails

Guard rails aren't strictly a type of rail as many different standard rails are used as guard rails. Guard rails (in UK/Europe) are only used to control the path of a rail vehicles when the normal guidance from the rails has failed. Guard rails only contact a train when things have already gone very wrong, i.e. derailment. Typically they are seen around bridges, tunnels and other vulnerable areas where a derailment could be catastrophic if the vehicle left the route. I included it here to clear up any confusion with check rails above.

Asymmetric rails

Asymmetric rails are just that – they aren’t symmetrical around their vertical axis. Sometimes called special or switch rails, they are often used for machining into shallow depth switch blades and are then forged to join with standard "full depth" rails, this range contains some weird yet wonderful profiles often essential for allowing traffic to pass from one track to another.

Thick web rails

These are flat bottomed rails but with an unusually thick web. Often found in switch and crossing applications used to construct rail turnouts/switches & crossings.

Conductor rails

Conductor rails are another unusual rail which trains do not run over with their wheels. This rail has one unique job, to conduct?electricity for the train to pick up and use. Because of their function these rails are a very different composition to normal railway rails. Steel versions have their composition is tailored to give a very low resistance to allow the efficient conduction of electricity. The electrical resistance may be around half that of a standard railway rail. Steel conductor rails also usually have a heavy section (to carry large currents), and a flat head to allow a good (sliding) electrical contact with the train. Aluminium conductor rails are lighter but must have a stainless steel cap to give sufficient wear resistance to the sliding electrical contact.

Piste rails

These unusual rails, which more resemble a construction section rather than a rail, are used in a fairly unique way too. They are used to provide the running surface for metro trains with rubber tyres. This transit system uses both conventional rails to support and guide the train, as well as rubber tyres to provide additional traction and braking forces above what a steel rail could typically achieve.

Because of their use as a rail running surface, their dimensional tolerances are far tighter than typical construction sections.

Bullhead rails

A bit of a peculiarity, bullhead rails are a historic invention, but still in fairly common use today in the UK where I'm based. It requires special housings for the rail to sit in and it is restrained with keys made from either steel or even wood.

Crane rails

Visually similar to flat bottomed rails – these aren’t usually grouped with railway rails as they are used in different applications. Symmetrical and having a flat bottom, their biggest difference to normal railway rails is their weight and much thicker web. This is needed to support very large axle loads from crane vehicles. Crane rails are also typically continuously supported i.e. they don’t sit on discrete pads/sleepers/ties.

Rail roundup

I hope you found something new/entertaining/insightful in this article. If not then give my other articles?a go and follow #rail101 for more rail related content.

Contact me?directly if you think I can help solve your railway issues.

If I've missed any names or important categories of rails then comment below too.

Send 'n' Share this to anyone who you think might like to learn a little more about the secret world of railways and a final thanks to my former employer British Steel for use of their rail profile images to illustrate the various types.