Bachmann 'Peak': Preparing the Locomotive

Dismantling the loco

Following the manufacturers' recommendations for running-in, ensure that the locomotive is performing smoothly and to your satisfaction generally. Deal with any issues now, especially those covered by warranty or your basic statutory rights as customer, before making any modifications.

Separate the body moulding from the chassis block of the locomotive according to the manufacturer's instructions. Store the body retaining screws safely away.

Select one of the bogies and undo the screw which retains the bogie pivot in the chassis block. Drop the bogie out from the bottom of the block. The cardan shaft joining the motor to the bogie will either come with the bogie or be retained at the motor end. Either way, remove it but note that the ears on each end of the cardan shaft are of subtly different shapes, so record which end is which.

Assign the bogie to one or other of your sets of etched bogie parts, marking the bogie drive and chassis block accordingly.

Similarly remove the other bogie.

Making up the Pivot Frame

Remove the Pivot Frame (P1) and Pivot Plate (P2) etches from the fret.

Check that the hole in the Pivot Plate is large enough to make a free running fit with the body of the M1.5 pivot bush fitted to the Bolster. Open it out with a round file if required.

Pivot Frame top flange Fold up the central flange of the Pivot Frame…

Pivot frame side flange …and then the side flanges…

Pivot frame side return folds …followed by the return folds in the sides.

Pivot frame side folds Fold in the sides of the Pivot Frame.

Pivot Frame and Plate assembled Fold up the flanges on either side of the Pivot Plate.

Adjust the folds in the Pivot Frame to fit the Pivot Plate, and solder the two together.

Reinforce the folds around the Pivot Frame with solder.

Pivot Frame retaining screw Take one of the M2 screws and nuts. Apply a thin film of grease to the underside of the screw head and the top few threads. Insert the screw through the top plate of the Pivot Frame, from the outside, and do up the nut on the inside. Apply flux and a good fillet of solder to secure the nut to the inside of the frame. Remove the screw.

Pivot frame bridging wire Take one of the smaller tag washers (P5). Solder a short piece of connecting wire to the tag, and then solder the other end of the wire to the Pivot Plate, positioned so that the tag is held approximately in line with the pivot hole.

The connecting wire can either be a piece of hook-up wire, as shown, or an uninsulated length of spring wire, in copper, brass or phosphor bronze. The tag on the washer supplied in the kit makes things a little easier than the arrangement shown here.

Fitting the Pivot Frame

Pivot tube fitting Open out, if necessary, the pivot holes in the chassis casting to be a sliding or loose fit for the 4mm brass tube supplied with the kit.

Pivot spacers Remove the four Pivot Spacer (P3) etches from the fret.

Within the bogie apertures in the chassis casting, degrease the area around the pivot holes and ensure that any lumps or bumps are scraped away. Check that the Pivot Spacers lie flat against the casting.

Pivot Frame on spacers Glue two of the Pivot Spacers, laminated one on top of the other, to the inside of the chassis casting. Centre them reasonably accurately over the pivot holes - they don't want to be touching the 2mm fixing screw when that is fitted. To hold them together while the glue dries, place the Pivot Frame over them…

Pivot Frame clamped …and clamp them up, from the top of the casting, using the 2mm screw and a piece of scrap etch. The jig pieces, removed earlier from the Inner and Outer Bolster legs, have holes etched in them for this purpose.

Finding spacer thickness Invert the chassis block, and offer up the Bolster into the bogie aperture, with the top surface of the Bolster Base resting on the bottom surface of the plastic chassis moulding. Use scraps of plastic card (probably 10, 20 and 30thou) to find the maximum thickness that can be placed between the Pivot Plate and the cross piece at the highest part of the Bolster Frame (remove the 1.5mm CSK pivot screw and fittings first), without lifting the Bolster Base away from the chassis moulding.

Spacer - insulators Cut two rectangles of plastic card 11mm x 18mm of the thickness determined above, with a 2mm hole made centrally 4.5mm from one of the long edges. Also cut four rectangles 11mm x 3.5mm from 20thou plastic card.

These pieces of plastic card serve both as mechanical spacers and electrical insulators between the Pivot Frame and the chassis casting.

Spacers glued to frame When the glue fixing the Pivot Spacers has set, remove the Pivot Frames from the loco and glue the 11 x 18 rectangles to the top surfaces of the Frames. Use the 2mm screw and scrap etch once more to clamp the joint flat. Also glue the 11 x 3.5 rectangles to the Frames, one to each side.

Pivot tube 1 Cut two lengths of the 4mm brass tube supplied, to pass through the pivot holes in the chassis casting and rest on the top surface of the Pivot Spacers.

Glue the brass tubes in place.

Pivot tube 2 Fit the M2 nylon insulators, supplied in the kit, into the tubes. Shorten each one, if necessary, so that it is supported by the underside of its top flange resting on the top of the tube, with its lower end clear of the top of the Pivot Spacer.

The M2 nylon insulator can be shortened by placing it over the shank of a 2.1mm drill, for support, then rolling it on the bench under a sharp knife blade to make the cut around its circumference.

Pivot Frame fitted When the glue has set thoroughly, fit the Pivot Frames into their bogie apertures, flat up against the Pivot Spacers, filing down the thickness of the 11 x 3.5 plastic spacers as required to give a snug fit against the sides of the apertures.

Remove the two etched M2 tag washers (P4) from the fret and place them on each of the 2mm screws. Refit the Pivot Frames to the chassis block, securing them with the screws.

Shorten the 2mm screws, as required, so that they end flush with the face of each fixing nut.

Pivot Frame on Bolster Remove the Pivot Frames once again from the chassis block and assemble them on to their respective Bolsters, using the M1.5 CSK screws, tag washers and M1.5 top-hat bushes. It's useful, for subsequent fitting to the loco, to arrange a bias in the wire to the tag washer that tends to lift the outer end of the Pivot Frame away from the Bolster.

Drive shaft access and viewing hole Make a hole in the plastic chassis undertray to allow you to see the UJ socket fitting at each end of the motor, taking care not to damage the fitting as you make the hole. Without sight of the fitting, it is very difficult to tell whether the driveshaft is correctly engaged.