In order to avoid too many electrically operated points on the exposed parts of my garden railway I have several points where the blades are moved by the passage of the trains themselves. A good example of their use is where a single track enters and leaves a passing loop. The blades are biased so that a train entering the loop will automatically take the left hand line, while a train leaving the loop will push the blades aside with its wheels.

Some method had to be devised to hold point blades in the biased position, but not to hold them too firmly, or the wheels of a train coming off the loop would be unable to push them to the opposite side. On consideration, a spring would not be the answer, as (a) springs are usually made of steel, which would soon rust, exposed to the elements, and (b) the pressure to push a spring would need to increase the more the spring is compressed. Something was needed that would lightly and positively hold the blade against the stock rail, but that could be easily pushed aside by the passage of wheels.

The answer proved to be a weight on a pivot connected to the end of the tie bar by a wire which either pulled or pushed the blade against the stock rail. See diagram1. The top picture shows the weight pushing, and the lower picture the weight pulling.

The weights I made are from 1mm thick brass, about 25mm long by 10mm high, the sizes not being critical. It just so happened that I had some 1mm thick brass, but I could have easily soldered together some thinner brass left over from a loco kit to make up near enough that thickness. The U shaped bracket is made from scrap etch brass and screwed to the track base. The pivot is an 8BA bolt. The upper hole in the weight is linked to a hole in the tie bar by a length of 22SWG nickel silver wire. A thicker wire would have been okay but anything thinner could be accidentally bent out of adjustment too easily. All the holes were drilled with generous clearances to ensure that there was no chance of friction. The wire was shaped in such a way that it kept the end of the weight just above the ground at all times.

The point blades also needed to pivot very easily, so were made no longer than necessary. The pointed ends of the blades were connected to the tie bar by long brass pins passing up through holes in the tie bar, then bent back and soldered to the bottom inside edge of the blades. The other end of the blades were pivoted in the same way, but to pieces of scrap etch soldered under the stock rails or under the closure rails. These pivots were made well enough to ensure that the blades remained upright and in line with the fixed rail. I have tried Peco rail joiners as pivots to save the complications of that just described, but found that they were not man enough to survive the rigours of a garden railway. The blades were electrically connected at the pivoted end to the stock rails by lengths of flexible wire “floppy” enough not to interfere with the easy movement of the blades.

In some cases I found that the weights were not quite heavy enough to pull or push the blades, so it was a simple matter to solder a little more material to the end of the weights to give them a bit more oomph.

See diagram 2 for the electrical connections. This also shows the one disadvantage of automatic points—the dead frog. The rest of the point blades, or closure rails, need to be cut at the spot before the back of the wheel flanges are at risk of shorting against the opposing rail. From there until beyond the V of the crossing the frog needs to be dead, which can be a problem for short wheelbase 0-4-0s unless they are fitted with a hefty flywheel. On my layout the shortest dead frog I have is on a Y point where diverging tracks are both at 6’ radius. That frog measures just 40mm, but I have found that on my largest radius automatic point that measurement increased to 70mm.

Diagram 3 shows how I have found automatic points useful on my own layout where a triangular junction off the “main line” leads into a terminus under cover in a shed. Only points A and D are motor operated for trains wishing to enter (or in the case of D, leave) the shed. B, C and E are automatic and I have drawn the blades to show which way they are biased. Point F has no control at all, as trains pass over it in only one direction, pushing the blades as they go.

Reliability? I have used automatic points for quite a few years and it is now a rare happening if one of them causes a problem unless it is an operators’ error. The classic “boob” is stopping a train when half of it has crossed a point, and then reversing! One requirement I have found by trial and error is to allow a decent amount of space around and below the tie bar so that one can easily remove debris which can accumulate there. I spend a few minutes before each running session to check and remove any bits of grot with a piece of bent wire if necessary. Lightweight plastic wagons benefit from the addition of some lead weight to help them push a blade over, but most garden railway owners will do this as a matter of course to lessen the effect of high winds. Loco pony trucks may also need a little “extra” to keep them down.