Thursday, 18 May 2017

Drag Boxes

Photos by Rob Bishop

The lack of recent news does not reflect a lack of recent progress. This report focuses on ‘new’ construction. KS4415 has never had a ‘drag box’ per se, merely couplings and buffers attached to the buffer beam. In early 1929,  KS4415 was fitted with chopper couplings to allow it to be used on passenger trains on the WHR. This is the period the restoration aims to represent. How the chopper couplings were fitted is unclear. Getting the coupling arrangement right is essential for the safe operation of the locomotive so we are shamelessly adopting current technology. To provide an idea about what we are currently fitting, here is ‘the answer’, in this case fitted to new FfR observation car 152.

Dragbox Assembly Car 152
The drawbar pivots in a crosshead. The crosshead is supported on two large bolts, with a series of rubber pads providing springing for both haulage and buffing loads. On KS4415 space to install this arrangement is limited, so rather than being fixed to a frame stretcher the dragbox assembly will be fixed to a strengthened buffer beam.

One of the crossheads for KS4415

The bufferbeam marked out for the new slot
to accommodate the coupling

Spare’ holes welded up, and new slot cut

A doubling plate has been fitted inside the frames

Having welded the old holes up Matty Wolstenholme drills
 a new row of holes. These will be used to rivet a pair of angles
 inside the frames which will carry the dragbox.

New holes, meet old holes

The angles used to fit the drag boxes to the frames
have been riveted in. The two bars labelled ‘top’ and ‘bottom’
are the start of the dragbox and are bolted to the angles.

The rear unit is more bijou.

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