Axle Load in a Railway.

General considerations about axle load in a railway and its importance in the design.
Axle load is the weight on the two wheels joined by an axle. (static vertical load per axle); It is, basically, the total weight bearing on the track.
If you have two wheels attached to an axle, with an AXLE LOAD P =225 kN, you have a load in each wheel of Q = P/2

  1. Step 1: Importance

    The axle load of a rail is an important design consideration in the engineering of railways. 

    It is determined by the weight of rails, the density of sleepers and fixtures, train speeds, amount of ballast, and the strength of bridges and earthworks.

    Axle load is the total permitted weight of a loaded rail wagon or a locomotive divided by the number of axles on the piece of rolling stock—is a critical measure of infrastructure physical capacity and strength

  2. Step 2: Axle load and structure

    That is, Axle loads are linked with the track structure. Heavier axle loads require a stronger track structure, which is expensive. 

  3. Step 3: Stress in railway structure.

    The purpose of the track is to transfer train loads to the

    formation. (Formation It is the surface on which the ballast is laid).

  4. Step 4: Basic design of railway.

    The basic principle for the design of the rail section is to have the optimum weight of steel, consistent with maximum possible stiffness, strength, and durability to provide a continuous level surface and adequate lateral guidance for the wheels rolling on it.

  5. Step 5: Section by weight.

    A rail section is designed for normal weight.

    Characteristics of Light Rail Europe for the profiles:

  6. Step 6: Shape

    Since the shapes are similar, the weight per meter is linked to Area, Weight, Moment of Inertia, section modulus, Height of neutral axis above the base, Lateral moment of inertia, Lateral section modulus of the head, Lateral section modulus of the base, Height of shear center above the base, Torsional rigidity.

  7. Step 7: Rail stress

    For this reason, axle load is not only linked to a rail profile. While all parts of the track structure are essential, that which is subjected to the greatest stresses and which is basic to the energy-saving efficiency of railroads is the rail. 

  8. Step 8: Values of axle load around the world

    The track is used by locomotives, coaches, and wagons which in Europe normally have maximum axle loads of 22.5 tons.

    Many older railways were built to a standard of 16 to 18 tons/axle. India, Russia,

    and China used 22.5 to 23.5 tons as the design limit. Heavy haul railways operate at

    32.5 tons/axle (standard in North America with some lines operating at 36 tons/axle); and a new special-purpose heavy-haul railway in Australia has been designed to achieve 40 tons/axle.