A turnout is the only place on a railway where the track deliberately breaks. The rails split, a wheel flange crosses a gap, and a thin steel blade decides which way a 5,000-tonne train goes. That is why turnouts take a share of track maintenance budgets far out of proportion to the length of track they cover.
This guide breaks a turnout into its parts: the switch, stock rail, tongue rail, crossing and the fittings that tie them together. It explains how each part works and what to look for when buying turnout components. We write as a manufacturer of thick web switches, CMS crossings and turnout fittings.
What Is a Railway Turnout
A turnout is a complete set of points and crossings, with lead rails, that lets a train move from one track to another. It sits at junctions, yards, sidings and crossovers.
Every turnout has two working zones:
- The switch (points): Moves to select the route
- The crossing: Lets wheels pass where two rails cut across each other
Left-Hand and Right-Hand Turnouts
A turnout is named by the direction the diverging track takes, seen from the switch end.
- Right-hand turnout: The branch line goes off to the right
- Left-hand turnout: The branch line goes off to the left
Turnouts are also described by crossing number, such as 1 in 8.5 or 1 in 12. A larger number means a flatter angle, a longer turnout and a higher permissible speed on the diverging route.
Main Parts of a Turnout
A standard turnout includes:
- A pair of stock rails
- A pair of tongue rails
- A pair of heel blocks or distance blocks
- Slide chairs and switch tie plates
- Stretcher bars
- Four lead rails
- One crossing
- Two check rails
- Fastenings, base plates and operating gear
Switch Assembly Components
Stock Rail
The stock rail is the fixed running rail against which the tongue rail closes. It carries the wheel load near the toe of the switch. Stock rails are bent or machined slightly at the toe so the tongue rail can tuck in tightly.
Tongue (Switch) Rail
The tongue rail is the movable, tapered rail that guides the wheel flange into the chosen route. Its thin end is called the toe. Its thick end is called the heel.
Here is a detail most people miss. At the toe, the tongue rail is too thin to carry the wheel’s weight. It only guides the flange, while the stock rail beside it takes the vertical load. The tongue starts carrying weight only further back, where it thickens.
Thick web switches use a tongue rail made from a heavier, asymmetric rail section. The extra web thickness makes the switch stiffer and longer lasting under heavy traffic. The heel end of this section has to be forged to match the standard rail it joins.
Heel Block
Heel blocks or distance blocks hold the heel of the tongue rail at a fixed distance from the stock rail. They keep the switch geometry stable under traffic.
Slide Chairs and Switch Tie Plate
Slide chairs support the tongue rail along its length and let it slide sideways between positions. A switch tie plate under the toe area holds both stock rails at the correct gauge.
Stretcher Bar
Stretcher bars connect the two tongue rails so they move together. When one tongue closes against its stock rail, the other opens by the right flangeway gap.
Lead Rails
Lead rails connect the heel of the switch to the toe of the crossing. A turnout has four of them, two straight and two curved. The curved lead rails set the radius of the diverging route.
Crossing Assembly Components
Point Rail and Splice Rail (Nose)
The point rail and splice rail meet to form the crossing nose, the V-shaped tip where two running lines intersect. This is the most heavily hammered spot in the whole turnout.
Wing Rails
Wing rails sit on each side of the nose. They support the wheel as it rolls across the gap in front of the nose.
Check Rails
Check rails are fixed opposite the crossing on the outer rails. They hold the wheelset sideways so the flange on the other wheel cannot strike the nose or take the wrong path.
Types of Crossings Used in Turnouts
- Built-up crossings: Made from machined rails bolted together
- Cast Manganese Steel (CMS) crossings: A single casting combining nose and wings
- Weldable CMS crossings: CMS crossings with rail legs flash butt welded on, so they can be welded into long welded rail track
- Spring and swing nose crossings: Close the gap at the nose for higher speeds
CMS crossings have an unusual strength. Manganese steel work-hardens under traffic, so the running surface gets harder as wheels pound it. The part that takes the worst abuse toughens up because of it.
Turnout Fittings and Fastenings
A turnout needs more fittings than plain track:
- Cast base plates for turnouts
- Elastic rail clips and liners
- Rubber pads under base plates
- Fish plates and bolts at joints
- Spring setting devices to hold tongue rails in position
- Gauge tie plates and anti-creep devices
- Point machine or lever connections
Loose or worn fittings are among the most common causes of turnout defects.
Common Turnout Defects
Track maintenance teams watch for a familiar set of problems:
- Gap at the toe: The tongue rail does not close fully against the stock rail
- Chipped or worn tongue tip: Raises the risk of a wheel flange splitting the switch
- Battered crossing nose: Wheel impacts flatten the nose and wing rails
- Worn check rail: Widens the clearance and weakens guidance at the crossing
- Loose fastenings: Missing or slack clips, bolts and base plates let geometry drift
- Gauge and alignment errors: Often the end result of all of the above
Many of these defects start from manufacturing tolerances. A tongue rail machined slightly off profile or a base plate cast out of square will show up as a field problem within months.
How a Train Moves Through a Turnout
- The point machine or lever sets the tongue rails for the route
- The wheel flange meets the closed tongue rail, which guides it
- The wheels roll along the lead rails, straight or curved
- Check rails hold the wheelset in line
- The wheel crosses the gap at the crossing, supported by the wing rail, then lands on the nose
- The train continues onto the chosen track
How to Choose a Turnout Supplier
Use this checklist:
- Approved designs for the rail section and crossing number you need
- Thick web switch capability, including forging of the heel end
- CMS casting and flash butt welding for weldable crossings
- Head hardening for longer rail life in switches
- CNC machining for accurate tongue rail profiles
- Complete set supply, including base plates and fittings
- Testing and inspection records for every set
Frequently Asked Questions
What is the difference between a switch and a turnout?
The switch is the movable part with tongue rails and stock rails. The turnout is the full assembly, including the switch, lead rails, crossing and check rails.
Why are CMS crossings preferred on heavy routes?
They are cast as one piece, so there are no bolted joints at the nose to loosen. Manganese steel also work-hardens under traffic, which improves wear resistance.
What is a thick web switch?
It is a switch whose tongue rail uses a heavier, asymmetric section. It offers better stiffness, longer life and lower maintenance than switches made from standard rail.
What does a check rail do?
It guides the wheelset through the crossing area so the opposite flange cannot strike the nose. It is essential for safe running through the crossing gap.
Conclusion
A turnout works only when every part, from the tongue rail to the smallest fitting, holds its geometry under load. The switch and crossing take the most punishment, so their materials and manufacturing methods decide service life. Buy them from a supplier that controls forging, casting, welding and machining in-house.
If you are planning a turnout upgrade or new yard, send us your layout and rail section for a complete turnout proposal.
Complete Turnout Systems from Jekay International
Jekay International Track Pvt. Ltd. has supplied railway developers, governments and private operators since 1980. We set up India’s first facility for end forging the non-uniform rail sections used in thick web switches and switch expansion joints. Our foundry casts CMS crossings and turnout base plates, our flash butt welding machine produces weldable CMS crossings, and CNC planers machine every switch to profile.
We promise complete turnout sets, from tongue rail to base plate, made and checked by one team.