Elimination of Camber setting in a Rail Coach Factory

Summary

The rail coach is assembled by using sub-assemblies such as Underframe, Sidewalls, Endwalls and Roof. Partition frames are welded and the shell is completed by welding all these and as a tubular construction. The camber setting is done on the Underframe. The Underframe is as shown below.

Camber setting for GS (General Second class) and SCN (Second class night coaches)

The Underframe is acting like a simply supported Beam and after welding is completed and the entire members are loaded, the underframe is assumed to become flat. The camber setting calculation is done. Assuming the entire Underframe is constructed as a box construction and the loads are applied.

The load is of maximum of 41.3 tonnes.

Table :

Analysis

The Underframe is 3D modeled using IDEAS software and analysis done as assuming a uniformly distributed load. Boundary conditions are selected and meshing done.

Pre-processor

Solver and post-processor done and the results are obtained.

15 mm

6 mm6 mm

6 mm

Shear force diagram

Bending moment diagram

Deflection diagram

Now the deflection of Underframe when subjected to Underframe only is analysed and the results are tabulated. In good olden days, there was no analysis software for analyzing the entire structure.

Our project is to eliminate the camber setting.

Here the camber setting is done in three stages.

i) Front camber is done during Underframe loading on jig.

ii) After fixing the Sidewall, welding is done and camber is removed.

iii) Again welding of Endwalls, Sidewalls are done and before placing Roof, camber is done and welding carried out.

Now the coach is surface modeled for 1/4th of the coach.

Nodes are applied with load.

Boundary conditions are applied.

Analysis carried out for vertical load.

SURFACE MODELLINGSURFACE MODELLING OF THE COMPONENTOF THE COMPONENT

FINITE ELEMENT ANALYSIS WITH VERTICAL LOADFINITE ELEMENT ANALYSIS WITH VERTICAL LOAD( THE ARROWS POINTING THE NODES)( THE ARROWS POINTING THE NODES)

Conclusion :

Since the maximum deflection is confined within 9mm even with vertical load + buffing load (which is an ideal condition where shunting is carried out in station along with passengers). Therefore, the deviation is well within the limits of our own decision of 10 mm as permissible limits. In the existing design, the coaches are noticed with 12 to 15 mm deviation after camber setting and final loading.

Hence the camber can be eliminated in the conventional coaches.

DEFLECTIONDEFLECTION