Model Railway Forum

Hi all
I have just recently taken up model railways, n-gauge, have got myself a small basic layout (DC) but was thinking of putting in point motors, recently bought two surface mounted motors (gaugemaster), but i have no idea on how to wire them or what I need (equipment wise) to achieve this, any help or diagrams would be greatly appreciated

Welcome to the forum. Friendly helpful bunch on here. I have no experience with those point motors, but I'm sure someone who has will be able to assist.

Welcome - My experience of wiring up point motors is ancient, from around 50 years ago in another lifetime. I'm sure someone will assist.

Hello and welcome.

Normally point motors are actually solenoids which need a sudden burst of current rather then a constant current. The burst of current should be just enough to throw the bar in the solenoid across. The current then needs to be switched off after it has thrown the solenoid over, so it is only a short burst of current that is needed.
This means that one has to be careful of how one is going to switch this current on and off to throw the point, so we will start with a suitable switching method.

The first simplest method is a tag and probe (Or called a stud and probe) where one wire from the transformer (Usually 16 to 18 volts AC. Use a cased transformer for safety as with open transformers one can accidently touch the mains so all transformers should be cased for safety even if they are on the underside of ones layout) will go to the probe which could be anything from a large nail or a metal pen to a commercially bought probe, and the tag or stud will be on ones control panel on a mimic diagram on the layout, and the wire from that tag will go to the point solenoids coil on one side. Another tag will be positioned on the control panel to throw the point the other way and this will go to one of the wires on the other coil of the point solenoid. the two other wires will be joined up into a single wire (Some point solenoids do this internally so only have three wires) and will be the "Common" return wire which will feed back to the other output wire from the transformer.
Thus when one briefly touches the probe to the tag (Which could be a little bolt head where the bottom of the bolt under the control panel has the wire wrapped around it and a nut screwed onto the back to hold the wire which then will go to one of the point solenoids coils) the point solenoid should (All going well) throw the point blades across.
Now instead of using a tag and probe, one can use a purpose made model railway point solenoid switch, or one can use a momentary switch. Momentary switches spring back to their centre off position when they are not switched. Momentary switches are listed in brackets when advertized like this: (On) Off (On) The (On) Off (On) type of momentory switch is the type you will need. DO NOT by ordinary On Off On type switches if one has a solenoid type point motor as these switches will stay in the on position which will burn out the coils of your point solenoid.

Now there is the possibility that one can hold the switch or the proble for too long and this will eventually damage the coils on the point solenoid though one really has to hold it there for a good while before one will damage it. Also, sometimes the point solenoid may stick and not always throw and could do with a bit of an extra boost of current. Now there is a device called a capacitor discharge unit which not only stores up current so when one wants to throw a point one will have a sudden extra boost of current which this device provides, but it also shuts off the current after it has been issued preventing the possibility in one burning ones coils out, so a capacitor disscharge unit is a useful device to get. It works by slowly storing up the current in the capacitors ready for when it is needed. When the current is needed and it is suddenly disscharged, it can't recharge until one has let go of the switch or the probe from the tag. Once one has, the capacitors will then recharge ready for their next use and so on. Due to the abaility for CDU's to add an extra sudden boost of current, one can also wire ones point solenoids up so that two points (E.g. at a point crossover) can throw at the same time, or if one wants to get really technical with simple electronics, one can use diodes and make a diode matrix circuit where several points can throw at the same time for specific routes... Though one will really need a more technical book before one goes down that route.


And finally. Some slow acting point motors are actual motors and are not solenoids and need to be switched differently so be aware of which type you have. These slow acting types will need a constant current rather then the momentary type current that solenoids will need. I have answered the above assuming that Gaugemaster sell the solenoid type of point motors. (It is confusing as they usually advertize point solenoids as being point motors where some types are actual point motors. The wiring principles remain the same but the switching method is not the same. DO NOT use a CDU if it is a motor type of point motor. The motor type point motors will normally run on 12v DC current rather then the 18v AC current that the solenoid type point motors run off.

To simplify point solenoid wiring in a form of a wiring diagram, the site owner has both written a book and also has a lovely detailed website that one can view that will give clear instructions to help you wire your layout, be it in DC or DCC forms. (I have not answered the wiring for DCC point control, but the principles remain similar except that a DCC points module will take the place of switches or tags and probe. When I was into 00 gauge and I bought a decent Lenz DCC system, I would still prefer to wire up points using the tag and probe method on a mimic diagram using a conventional control panel as I find it far more straightforward and easier to use then to throw points via one of my DCC hand controllers. The only real advantage that I saw in using DCC to control points is when one wants ones layout to operate automatically via a computer interface which to me kinda spoils the fun of operating ones trains!).

Welcome,
see link https://www.brian-lambert.co.uk/Electri ... otorwiring

I enjoy seeing anyone's work, and I particularly enjoy first attempts, and the like. I hope you will find time to post.

Welcome Lolly58 - you have joined a great forum.

Welcome to the friendly and helpful forum.

Mountain Goat wrote: ↑Sun Sep 12, 2021 10:30 pm Hello and welcome.

Thanks Mountain Goat for your reply.

Mod Edit: Lolly I have edited your reply - you just need to use the reply box to make a response and you don’t need to alter the title. If you want to reference a long post in your reply, please paraphrase it. Thanks RogerB

Lolly58 wrote: ↑Mon Sep 13, 2021 6:43 pm Thanks Mountain Goat for your reply.

You are welcome. See the link that dtb posted.