(Click on the thumbs for a larger pic.)

Points (switches) on the Emu Mountain layout are controlled, in the main, by "Armstrong" levers. That is - to change the point - you pull the lever! There's nothing quite like actually pulling the lever and watching the blades move across to change the points. Ask my 2½ year old grandson! He has road tested all of my points and all passed with flying colors!

Above: Armstrong Point Control on Woody's Emu Mountain Layout

This operation method works for both spring loaded (Peco) and non spring loaded style points (Shinohara) because the actuating cable holds tension and keeps the point blades in contact with the stock rails.

The basic concept comes from the Castlehill layout of the late Ted Tudor - Melbourne, Vic. The vast majority of points and signals on that layout are operated by this method. I have adapted the mechanism, particularly the lever frames, and provided for cable adjustment.

There are two main aspects to the concept - the lever frames and the point blade changing mechanism.

Lever Frames

The lever frame is made of two angle bracket pieces mounted on timber. Between the angle brackets is a threaded rod and on the rod are the levers separated by slightly oversized nuts and washers.

Above the levers - mounted on the edge of the timber is an electrical terminal block.

Each bracket is 55mm long, cut from 50 x 50 x 2mm mild steel. My local steel supplier pre-cuts the angle brackets for me for a nominal fee. I drill two mounting holes on one face of the angle bracket and a ¼" (metric??) hole for the threaded rod on the other face. These are all done with a jig and drill press.

The 100mm (4") long levers are also pre-cut by my steel supplier. They are made from 12mm x 2mm mild flat steel. I drill a ¼" hole down one end and a smaller hole in the middle.

Once I have drilled all the holes, I curve and smooth the ends of the levers on the bench grinder. Then all the levers and brackets, together with the timber mounting board, are painted with Hammerstone spray paint.

As mentioned earlier, the levers are mounted on a ¼" threaded rod with slightly over sized nuts and washers as spacers to line up the levers with the holes in the electrical terminal block. The rod has double locking nuts at the angle brackets.

The electrical terminal blocks that I use are each 12 units long. I link two together - 24 levers - where I have large yards with lots of points. The electrical terminal block holds the cables firm at the lever end and allows for adjustment of the cable. Some older ones I used had a slightly larger hole and the curtain cable passed through easily.

On the later units there is a flat plate that the locking screws press down on. I now drill out the hole with a ?" drill removing that plate. Once that is done, the cable fits just fine.

Points Component

The components need for installing the system at the points end are the bell crank, a length of piano wire, a length of plastic coated wound curtain cable, one screw and washer and a staple.

I buy my piano wire from a piano tuners supply store and I bought my plastic coated curtain cable as a complete roll through my hardware shop. I'll have enough cable for 10 layouts I think!

The bell crank is made from fairly thick styrene. I have some .40 and .60 scraps that I have used with success. Others I know have made their bell cranks out of metal or heavy plastic like Perspex but I have had no problems with the ones I have made. I cut the styrene with side cutters! I drill three holes - as shown; one each for the piano wire cables and the other larger hole for the pivot point screw.

The bell cranks (and screws) can be painted black at this stage or later when installed. I usually do it later, because I make the bell cranks as I go - and forget the paint them until it's too late!

Make a long flat U shaped push rod to go between the point push bar and the bell crank. Leave the legs longer at this stage. They can be cut down later. Oh yes, make sure you are using good quality side cutters that will cut piano wire!

Loosely fit the bell crank in place allowing for the directional push pull needed to actuate the point. I drill a screw sighter hole at this stage. Do not mount the bell crank into position yet.

Line up where the actuating cable will need to come through the baseboard. Drill a ?" hole on as flat an angle as possible through the baseboard. I invested in an especially long drill for this. Well worth it.

Cut the curtain wire allowing for a gradual curve back to the lever frame. Strip about 120 - 150mm (6"-7") of the plastic from each end. Push a scrap piece of piano wire down the hole in the baseboard. This serves as a guide for the curtain cable. Push the curtain cable back up through the baseboard to within 25mm of the bell crank.

Feed the other end of the curtain cable through the mounting block holes of the lever frame. Lightly screw them in place for the moment. Pass a length of piano wire through the cable starting at the lever frame end. When it pops out at the point end, fold a right angle bend (about 10 - 12mm) in the cable and it's ready to be installed into the bell crank.

Put the washer under the bell crank and screw down the bell crank. Make sure it's not so tight it restricts movement. It only has to hold it in place. Then staple down the cable end. I drill two small sighter holes to help hold the staple. Tap in the staple with the hammer and test the point with the piano wire at the lever end. Again don't squeeze the cable with the staple. The piano wire has to be able to move freely.

Now you can cut the piano wire at the lever end. It needs to be about 150 - 170mm (6" - 7") longer than the curtain cable. Release the curtain cable tension and pull the cable through to give some room to work (about 70 - 80mm). Pass the piano wire through the small hole in the lever leaving about 25mm (1") from the cable end to the lever. Wrap the piano wire around tightly. Cut off any excess.

Now for the adjustment.

Slide the curtain cable back until all the point levers are in line and then lock them off with the terminal mounting block screws. Too easy!

Number the point lever.

Now go back and paint the bell crank and screw black. I use a black marker pen - works just fine! Put oil on the shaft especially if you will be using diluted white glues for scenery or ballast. Trim off the legs of the point push rod - or the trains won't go anywhere!

Extra points to consider.

If there is thick underlay, it is worthwhile to place packing of some sort under the point throw bars to hold the push rod in place.

My layout - and the ones I've seen using this system, are all on plywood. You need a firm strong base to hold the staple.

You can link two points (two cables) onto one lever or link two points together activated from one lever - one point controlling the other. This especially applies where two points must always operate together ie: a crossover. I have tried both methods but prefer a separate lever for each point. Levers can be bolted together so they must always be operated as a pair. It works well.

This Armstrong concept works fine with DC or DCC systems. However, it does rely on contact between the point blade and the point stock rails and is very good with insulated points. It will work with electrofrog points but make sure there is good contact before you start.

To solve the possible problem of poor contact and live frog points, Bob Mitchinson has designed his levers as separate units that all bolt together. He has mounted micro-switches onto the side of the mount and the lever arm activates the switch. He has also mounted micro-switches on the point throw bar.

His units are laser cut metal in the shape of a real signal lever and are beautifully designed. They are very light in construction but I'm not sure how well they would pass the 2½ year old grandson test! The ones on Emu Mountain are rugged and have withstood the rigorous treatment a little train enthusiast can deliver.

Happy modelling - especially "Armstronging!"

Copyright © Paul Woodward 2006