How are train wheels designed?
Wheels are initially cast or forged and then heat-treated to have a specific hardness. New wheels are machined using a lathe to a standardized shape, called a profile, before being installed onto an axle. All wheel profiles are regularly checked to ensure proper interaction between the wheel and the rail.
What are the wheels on a railcar called?
A wheelset is a pair of railroad vehicle wheels mounted rigidly on an axle such that both wheels rotate in unison. Wheelsets are often mounted in a bogie (“truck” in North America) – a pivoted frame assembly holding at least two wheelsets – at each end of the vehicle.
What is railway wheel profile?
An effective wheel/rail profile design incorporates a tapered wheel tread to generate the rolling radius difference (RRD), which promotes steering in curves and has a significant influence on the dynamic vehicle performance, overall [6. I. Y. Shevtsov, V. L. Markine, and C.
Why are railroad wheels tapered?
The taper of the wheel rims keeps a train on its tracks, not the flanges. But if an emergency occurs, you’ll be glad the flanges are present.
What material are train wheels made from?
steel
The wheels will be made out of steel, and they are made out of steel for a few reasons. First, did you know that road vehicles lose a ton of energy just by pushing its tires down the road? Tires made out of rubber bend and they wear out relatively quickly.
How many wheels train have?
Railway wheel is assembly of two wheels fixed to the axle by interference fit and they rotate along with the axle, without any independent relative movement as in the case of other automobile wheels. 1 Tensile Strength at 15 mm below tread face 900 N/m2 min.
How does a rail wheel work?
When a train with slanted wheels turns, centrifugal force pushes the outside wheel to the larger part of the cone and pushes the inside wheel to the smaller part of the cone. As a result when a train is turning it is momentarily running on wheels that are effectively two different sizes.
What shape is a train wheel?
Train wheels are conical in shape. That means they have a varying diameter at different points of contact.
Why are rail wheels conical?
The wheels on each side of a train car are connected with a metal rod called an axle. This is where the wheels’ geometry comes in. To help the wheels stay on the track their shape is usually slightly conical. This means that the inside of the wheel has a larger circumference than the outside of the wheel.
How thick is a train wheel?
Tires are reasonably thick, about 3 inches (76 mm), giving plenty of room for wear. Worn tires or tires with flats are reprofiled on a wheel lathe if there is sufficient thickness of material remaining.
Why are there rocks on railway tracks?
1. The stones don’t allow vegetation to grow on railway tracks which could weaken the ground on which the railway lines run. 2. Track ballast also keeps water from reaching the track on a regular basis and softening the ground.
What are the steps in designing a railway track?
Design Steps (AREMA, U.S. DoD, and Others) (Generalized) 1. Select design wheel load based on most common, heaviest car and desired track speed. Consider all wheels in a truck and proximity of adjacent cars. 2. Select a Track Modulus, u or k, based on desired design deflection 3. Select rail size and section 4.
What are the different wheel diameters for rail?
5 Different Wheel Diameters 38 inches 28 inches 36 inches 33 inches 36 inches 6 Track Stiffness • Rail is assumed to be a beam on an elastic foundation • Modulus of Track Elasticity, u (or k) (a.k.a. Track Modulus) u = P/Δ
What is the guidance mechanism for railway vehicles?
The guidance mechanism for railway vehicles is defined almost exclusively by track location and thus the track alignment. The operator only has direct control over longitudinal aspects of train movement over an alignment defined by the track, such as speed and forward/reverse direction.
What are the characteristics of mild wheel/rail profiles?
• Wheel / rail profiles and vehicle steering behavior are such that the curve can be considered “mild” • The contact area at each wheel tread / low rail interface is approximately circular, with a typical radius of 7mm. • The rail steel can be assumed to have a shear yield strength of k=70 ksi.