Dismantling 2 - Everything but the engine

The cab was suffering from serious corrosion.  The cab consists of several panels of 4mm and 5mm steel joined by angle iron or flat steel strip.  These parts are fastened by a mixture of round-head 3/8” Whitworth bolts and 3/8” round-head rivets.  The cab opening is edged with steel strip known as “half-round feather edge”, which is riveted to the panels.  Rust had formed between the panels and the angle iron and also between the panels and the half-round feather edge, and as corrosion progressed the panels had buckled between fixing points due to the expansion of the rust.  The panels had also corroded through in a few places.  The fact that the panels had been distorted and the extent of the corrosion meant that the panels, angle iron and feather-edge were all scrap.  However they would be kept to provide a reference for making new parts in future.

Before dismantling the cab, the electrical system was removed.  The electrical system is very simple and consists of a control box with a key switch (the control box had been levered open and the key switch stolen) and four push-pull switches for lights (front, rear and cab) plus engine start.  A push-button on each side of the cab operated the horn.  All wiring within the cab used brass-bound armoured cable.  The control box, cabling, switches, lights and horn were all removed and set aside for restoration.  The large wooden tool / battery box was also removed for restoration – the lower half had partially rotted, but it was restorable.

The upper front of the cab, showing the corrosion and buckling at the edges

A few cab bolts were salvageable, but most were removed using an angle grinder.  The roof was the first part to be removed.  Its shaped angle irons and the roof sheet itself were salvageable, but the feather-edge would need to be replaced.  The roof rear end was bent by the chains when Queen Anne was lifted from its siding, but could be straightened.

The lower rear cab panel

The original design of the cab had a horizontal sheet of metal from the lower edge of each cab side to the main chassis girder (this part is below the cab floor).  It was a trap for dirt and moisture and was the most corroded part of the whole locomotive.  This will be redesigned in future to eliminate the rust trap and improve the method of fixing the floor.

Badly designed bodywork

The chassis is formed from substantial rolled steel sections (mainly U-channel) from Lanark steelworks and welded together.  There was some localized corrosion (particularly where the rot-trap above was bolted on) but the substantial nature of the steel ensured it was not a problem.  There was quite a bit of corrosion (and a mummified rat) in the area of the sandboxes.  This was because sand would get spilled when filling the sandboxes and go through the gaps onto the chassis below.  A small part of the chassis was ground back to help any sand drop onto the track.

In one place this corrosion had extended to the nut on the back of the buffer that retains the buffer spring.  Also, one of the fixing bolts for each sandbox is hidden behind the buffer, so all four buffers had to be removed to enable the nut to be replaced and the sandboxes to be refurbished.

The brake gear was stripped off and was basically serviceable (but partially seized), although the pivots that take the brake blocks were a bit worn.

The suspension uses leading and trailing swinging arms pivoted around the centre of the locomotive.  The pivots are approximately coincident with the sprockets that drive the wheels via chains and this ensures that the chain will not come off as the wheels go up and down.  Because the drive sprockets for the front and rear chains are on the same axis, this alignment cannot be exact for both axles.  By making the length of the swinging arms adjustable, the chain tension can also be set.

The axle bearings were found to be in good condition.  A bronze bush spanning 180 degrees of circumference bears on the steel axle which is lubricated by an oil pad.  All suspension parts were cleaned up and put back.  Leaf springs are used, with the upper (largest) leaf bearing on one of the chassis girders.  This allows the springs to move laterally as the length of the suspension arms is altered.  The upper leaf on one of the wheels was found to be broken, but was welded back together.  This spring will be monitored to see if the repair holds.

With everything stripped, the suspension is being attended to

Practically everything was stripped from the chassis, leaving it with just its wheels and the engine block and gearbox still in place.  The long process of examination, refurbishment and reassembly lay ahead.