We have not produced an install video for Roundhouse Katie yet.

Most of the install procedure for Katie is the same as for Roundhouse Billy and the Darjeeling. Install

videos for both, are available on this site. Also see the excellent notes below, compiled by Chris Bird in the UK

during a Slomo installation that he carried out. The section titled Re-aligning the weigh shaft , describes realigning the weigh shaft in Katie

which would otherwise jam on the top of the Slomo. The weigh shaft procedure  is not necessary when installing a Slomo in Billy or Darjeeling and,so

the available videos do not cover this part of the installation.


Slomo Roundhouse Jack(Katie) Fitting Notes.

What is involved
Fitting a SSP Slomo to the Roundhouse Jack is relatively straightforward and involves five main operations:
Removing the body
Re-aligning the weigh shaft
Fitting the Slomo
Checking and adjusting the weigh shaft.
Re-fitting the body

1. Removing the body
On many types of loco it will it will not be necessary to remove the body, but on Jack(Katie), the large tank prevents easy access to the

grub screws on the lifting arms.

First drain the lubricator or suck out the contents with a syringe. When empty, remove the lubricator drain screw and put it somewhere safe

(that applies to all parts removed!).

The body is held on with one large screw in the centre of the dome (saddle tank filler) and one in the centre of the rear buffer beam, above the

coupling. Remove these and carefully ease the body up and off the loco.

2. Re-aligning the weigh shaft.

The weigh shaft is the cross shaft that runs across underneath the boiler to join the two lifting arms. On most locos it has a curved centre section

that dips down in the centre. This would foul the Slomo and so it needs to be re-aligned.

First set the loco in full forward gear. Now loosen the grub screws with the correct size Allen key (there will have been one supplied with the loco).

If the grub screw will not loosen, then a little heat applied to the fitting with a micro torch (not a full size blow torch!) will free it.

With both screws loosened, rotate the shaft so that the curved part moves back and up until it touches the boiler. Check that both sides are still in

full forward gear. Now ease the weigh shaft down a couple of millimetres from the boiler and tighten the grub screws.

Check that it operates correctly – but don’t be too worried at this stage if it is not spot-on.

Fitting the Slomo
The Slomo will fit between the frames and between the axles. In order to do this, and fit the chain sprocket, it is necessary to disconnect the valve gear and

withdraw the rear axle.

Before starting, find something that will allow you to work on the inverted loco without damaging it. I use a bean bag, but a folded towel (not the best ones!)

or a piece of polystyrene foam will do.

First remove the rear cranks with all the gear still connected. To do this find the correct sized flat bladed screwdriver and loosen the screw in the centre of the crank.

Unscrew it about half way – but do not remove it. Now holding the screwdriver squarely on the screw, give it a sharp tap with a small hammer. This will release the

crank from the square shaft

allowing you to remove the screw and separate the crank from the axle.

Repeat this the other side.

Now undo the grub screws securing the wheels with the correct sized Allen key. It should now be possible to slide the axle to one side and remove one of the wheels.

Leave the axle in place, pulled through to one side.

If the wheel is very stiff on the axle, then ease it by holding it with one pair of grips while rotating the axle with another. Protect the metal if you are doing this

(I used two scraps of canvas).

Finally remove the two 6BA screws holding the central frame spacer and remove it.

3. Fitting the Slomo
Take the Slomo and check that the chain is on the small sprocket. Remove the socket headed screws holding the frame clips in place.

Now take the O rings and press one into each of the three recesses machined into the frame sides. These are to insulate it from the frame and reduce sound transmission.

Next, carefully lubricate each of the bearings with a little light machine oil (motor oil is OK). Wipe it clean.

Now you can slide the Slomo between the frames, with the flywheel facing forwards and with the deep cut-outs towards the boiler.

Place the large sprocket on to the axle with the boss away from you (if the smokebox is to your left). If it is reluctant to go on to the axle, check the grub screw is

loose and, if necessary, de-burr the grub screw hole.

Now fit the chain over the large sprocket, fit the second wheel and push the axle fully back into place. Do not re-fit the cranks at this stage as you need to be able

to screw the clips into place.

Fit the clips to each side. The larger one fits in the rear of the frame cut out with one bolt and the smaller one fits vertically in the front of the slot with two. If necessary

you can move the Slomo to align the holes.

Before final tightening, check that the chain is tight with just a little play. Apply a little oil to the chain.

Now re-fit the cranks (with the rods coupling rods correctly aligned) and use the screws to press them back into position.

Stand the loco on its wheels and the

4. Checking and adjusting the weigh shaft
This may not be necessary, but it is worth checking before the body goes back on.

Turn on the radio control and check that the forward and reverse on both sides is correctly adjusted. The lifting arms should move the block nearly to the top of the

expansion link in reverse and nearly to the bottom in forward.

When this is fine, then check the tightness of the grub screws.

5. Re-fitting the body
Take care that the sanding tubes fit correctly as you lower the body back into position. Secure it in place with the two screws.

Replace the lubricator drain screw.

Job done!