Temperatures at railway tread braking. Part 3: wheel and block temperatures and the influence of rail chill

Abstract

Tread braking generates high temperatures in railway wheels and brake blocks as the kinetic energy of the running train is transformed into heat. The temperatures induced in the components are here analysed with particular focus on the cooling influence from the rolling contact between the hot wheel and a cold rail. Controlled brake rig tests are reported, where the rolling contact is studied using a so-called rail-wheel in contact with the braked wheel, along with results from field tests. The data from these experimental studies are used for calibration of a simulation tool for calculation of wheel and block temperatures. The calibrated model analyses heat partitioning between block, wheel and rail and finds the resulting temperatures at braking. The rail chill is found to have a considerable influence on the wheel temperatures for long drag braking cycles. A successful calibration of the model using data from field tests is also reported.

Thermal load effects on fatigue life of a cracked railway wheel

“…As can be seen from data of this table, equivalent stress intensity factor obtained from thermo-mechanical analysis is considerably greater than the corresponding value of mechanical analysis which means that the stresses of crack tip may be increased due to thermal loads of braking.Also, from this Temperatures indicated in Table 4 are representative of the maximum temperature of tread wheel during the braking step analysis. For the angular velocity of 100 rad/s, the result obtained from Abaqus thermal analysis is 424.5 o C which is analogical to the thermal image generated by thermo camera in a brake rig experiment (Vernersson and Lunden, 2007). Also according to Fec (1985) tread surface can reach temperature of 300-400 o C.…”

Finite element modelling of frictional thermomechanical rolling/sliding contact using an arbitrary Lagrangian–Eulerian formulation

“…To an extent, the large difference in magnitude is due to convective effects: heat is transported out of the considered plate domain while cold material is transported into it. Note, however, that these quantities are not readily comparable, due to the inherent arbitrariness of the mean temperature measure (21) and the volume over which it is taken. Figure 13 shows the temperature distribution for the case where the rotational motion of the cylinder is locked ( ¼ 2) -which means that the convective velocity in the cylinder domain is zero.…”

Thermal models of railroad wheels and bearings

“…Using these variables, and dividing by P, the above differential equations may be written (19) (20) (21) These equations can be stated compactly by consolidating the coefficients of the temperature terms on the left side in the form (22) (23) (24) where The above coupled first-order ordinary differential equations were solved numerically with a Runga-Kutta method. The numerical solution was checked against an analytical solution for the special case h 0 =0 (a two-lump version of the model).…”

“…Recently analytical modeling and experimental efforts have been combined to determine the heat generated at the wheel and rail interface [17][18][19]. These studies have resulted in a theoretical model that predicts the thermal behavior of the contact area between the wheel and track when the brakes are applied.…”