Friday, 1 September 2017

Commonwealth bogies

After the holiday break! well mine anyway!

Whilst I have been away the lads at the shed have been refurbishing a pair of commonwealth bogies.  Although these bogies are currently under the RU, they are destined to be used under the P-way departments BG mess vehicle.  The reason for this is that we have utilised four axles that have had their tyres re-profiled, resulting in the tyres now being under the minimum thickness.  The p-way BG is sitting on bogies that have very good tyres, with plenty of use left in them, hence they are required for the RU.  The undersized tyres will be perfectly good for the limited use that the p-way vehicle gets.

A commonwealth bogie minimum tyre thickness is 35mm and the wheels that we have used have a tyre thickness of 32 / 33mm.  The 35mm minimum is for a bogie which will run at 100 mph, so at our maximum speed of 25mph, 32/33mm is probably fine, however we work to the former British Railways standards for coach repairs.

The replacement axles pictured inside the shed, having been needle gunned cleaned and painted.  They are at the undercoat stage.

A Commonwealth bogie is fitted with roller bearings, as these axles have been standing outside for a long time the rollers needed cleaning, the grease needed replacing with new gaskets being fitted to the bearing caps.

A Willie Dodds paint special!  not so sure that white gloss is a good idea, however it certainly creates an effect,  Gloss black tyre rims to finish.

 Bogie number 10 completed.  This has been a huge learning curve for us, we have changed axles and horn guides before, but we have never changed the centre coil springs on the bolster. 

The bogie has six coil springs each side, the centre springs have an inner and an outer coil.  When it was dismantled, one of the inner coils was found to be broken, with the top and bottom mounting pads completely disintegrated.  A replacement spring was sourced, new neoprene pads made and the original steel discs cleaned up and painted.


  1. Can I ask why the wheels have the four holes drilled in them. I guess the smaller holes are for balancing (photo above, LH wheel), but not the evenly-spaced four. I've followed the blogs with interest, and appeared sometimes in 'On track...'

    1. Bruce
      The honest answer is that I don't know. All of our wheels have them, which modern railway wheels don't seem to. It caused problems when we sent some away to a large railway engineering company for re-profiling, they would only do the job if we signed an indemnity for them. You are correct thet the small holes are for balance weights.

    2. Could the reduction in unsprung mass be an answer to the hole query. There is surely sufficient mass in the wheel itself to permit of some redundant metal removal.