How to fit lights to a model railway?
This article will cover the basics of installing lighting accessories on your model railway with use of the ModelSigns Model Railway Lighting Wiring Starter Kit in mind. We recommend using ModelSigns Lighting Accessories, but third party lights can also be used in this set up.
A - 20x 1k ohm 1/2w Resistors
B - 1x Terminal Block to Barrel Plug Connector
C - 5x 20cm Black Heat Shrink Tubing
D - 1x Wire Stripping/Crimping Tool*
E - 30x Crimp Blade Splice Connectors
F - 30x Male Tab Connectors
G - 1x 12v 2a Power Supply/Transformer with UK plug
H - 5m Black 2mm Multistrand Wire
I - 5m Red 2mm Multistrand Wire
J - 3m Black 1mm Multistrand Wire
K - 3m Red 1mm Multistrand Wire
* - Not included in basic kit
While the kit includes all of the materials you should need to wire your lights, you may need a few extra items depending on how you intend to install the kit and the construction of your layout. These are -
Pliers – Required
Drill (with various drill bits) – Required
Screwdriver (with No. 1 Cross Head) - Required
Crimping Tool – Required (Included in Full kit)
Wire Striping Tool – Required (Included in Full kit)
Cable Clip – Optional (Depends on baseboard construction)
Adhesive Cable Clip - Optional (Depends on baseboard construction)
Pluggable Terminal Blocks – Optional (Required for multi-board layouts)
Step 1 – Running the bus wires
The ‘bus’ wires will be the main two wires [Parts H & I] that run the length of your layout and are used to power all of your lighting accessories. Depending on the dimensions of your layout these should be arranged in such a way that it is possible to reach them from any area where you wish to have lighting on the surface of the board without the need for exceptionally long wires from the lights themselves. On larger layouts, or those with many lights, it may be necessary to purchase additional lengths of wire, this is available from the ModelSigns store. While it is important to have the bus wires near to where lights will be installed, try to avoid placing them directly beneath to avoid drilling into the wires when installing lights. At this stage do not cut the ends of the bus wires, additional wire should be looped at the end and can be trimmed once installation is complete. See some examples below.
Depending on the construction of your layout there are several different possible mounting options.
Option 1 – For layouts with horizontal joists supporting the baseboard simply drill 2x 3-4mm holes through each joist and feed the bus wires [Parts H & I] through these holes, allowing the wire to run around the underside of the layout. Take care to avoid any screws used to secure the board to the joist. This method should allow you to easily hang the wires underneath the layout without a need for any additional cable clips.
Option 2 – On layouts that have been constructed without horizontal joists, or on layouts where it is impractical to drill through the joists it is possible to use cable clips (not included) to suspend the wires from the baseboard. However, care should be taken to make sure that a) the pin on the clip doesn’t pass through to the other side of the baseboard, b) the bus wires aren’t damaged or compressed by the clip/pin and c) that the wires are held in place securely with little chance of them falling as this could present a safety issue.
Option 3 – Like option 2, this should can be used on layouts without joists, it can also be used in addition to Option 1 to provide additional support for longer spans between joists. This option is primarily aimed at layouts where the baseboard is too thin to comfortably accommodate a cable clip with a pin, although do note that it is potentially less secure. In this situation is is possible to use adhesive cable clips (not included) as these don’t require a pin to be hammered through the baseboard.
Step 2 – Adding Lights
After fitting the bus wires the following step is to start to add your lights. When installing lights to your layout follow the instructions provided by the manufacturer. For ModelSigns lights these manuals can be found here.
A condensed set of installation instructions for ModelSigns lights would generally be as follows-
1) Mark the intended location of each light on the baseboard from above. Make sure you will be able to drill though your baseboard in this location and that you’re not going clash with a wire, a joist or point motor underneath the board.
2) Carefully drill through your baseboard in the marked positions. Be sure to drill a large enough hole for the resistor and wiring to fit through.
3) Prepare your lights for installation by -
i) For standard ModelSigns lights designed to operate on 3v, solder one of the supplied resistors [Part A] to the negative lead from the light and cover with a small length of heat shrink tubing [Part C] taking care to cover all exposed wire. Carefully use the side of the soldering iron to activate the heat shrink tubing. This step can be skipped for ModelSigns Premium lights as they are designed to operate directly from a 12v supply and generally already have resistors attached.
ii) Check to see if the wires attached to the light are long enough to reach the bus wires from their intended location without being strained, if not, use the 1mm wire [Parts J & K] to to extend the wires so that there is a comfortable amount of slack to reach the bus wires (this can be trimmed later if too long). Again, use heat shrink [Part C] to cover any exposed wire to prevent short circuits. Standard wiring convention is to use black wire for the negative lead and red for the positive, try and stick to this to simplify the installation process
Customers with the Wire Striping Tool [Part D] can use this to cut and strip the wires.
To cut the wire, place it inside the jaws of the tool next to the blade marked ‘WIRE CUTTER’, squeeze the handles and the wire will be cut.
To strip the ends of the wire, place it inside the stripper head on the top of the tool as shown. The right hand pincers mark the point at which the insulation will be trimmed. Squeeze the handles and the tool will remove the insulation.
.4) Once you have added any required resistors or additional wire length you can continue to fix the light in position on the layout as per the manufacturers instructions.
5) Once the light is fixed in place and the wires fed through to the underside of the baseboard it is time to attach the Male Tab Connectors [Part F] to each of these ‘droppers’ (the wires that *drop* through from above the board).
i) First, prepare the end of the wire for insertion into the connector. If you haven’t already, strip a small amount of wire insulation from the wire (≈ 10mm), then twist the wire strands and fold them back on themselves. For close clusters of lights it is possible to twist several droppers (of the same polarity – DO NOT mix red and black wires) together and fit these into a single connector.
ii) You can now insert the end of the wire into the connector, stop the wire just short of the opening at the end of the spade.
iii) Place the connector and wire into the jaws of the crimping tool [Part D] next to the red dot, or for connectors filled with only fine wire, next to the 10-22 mark may work better (as seen in the below photo). Then squeeze the jaws of the tool to secure the wire in the connector, this may require a reasonable amount of force compared to what is required for wire cutting or stripping.
iv) After crimping the wire should be well secured in the connector.
Step 3 – Connecting lights to the bus
1) The next step is to fit the Crimp Blade Splice Connectors [Part E] to the bus wires. You will need one blue connector for every red tab connector. These should be positioned near to where the droppers come through the board and ideally with the connectors on both the black and red bus wire positioned closely to each other to make wire tracing easier. To fit a blue connector simply position it around the bus wire as shown in the image below with the wire sat in the small groove within the connector.
2) Use a pair of pliers to squeeze the two sides of the connector together, clamping down on the bus wire. The connector should make an audible click (or the small plastic latch should be seen to have clipped into place on the upper half of the connector) as seen below.
3) The red tab connectors can now be inserted into the slot on the end of the blue connectors for both the positive/red bus and negative/black bus. There should be an obvious click when the hole in the middle of the tab slots into place within the connector. It should now require a reasonable amount of force to pull the red tab out of the connector if done correctly.
4) Before adding any more lights it is advisable to test to make sure the circuit is working as this simplifies the troubleshooting process.
Step 4 – Connecting the bus to the transformer
STOP! Before proceeding check that all connections are secure and that there are no short circuits, this could cause major damage to both any lights connected and the power supply. Ensure there are as few exposed metal surfaces as possible. Also double check that the polarity of every connection is correct, DO NOT mix positive and negative cables! As with any installation involving electricity it is advisable to have a qualified electrician verify the integrity of the work.
1) Once the system is determined to have been safely assembled, trim a small amount of the insulation from the end of both the black and red bus wires.
2) Then insert each of the bus wires into the barrel plug connector [Part B], with the black bus wire going in the terminal with the negative symbol above it and the red bus with going into the terminal with the positive symbol above it. Take care to ensure sure there is as small an amount of exposed wire showing outside of the terminal as is possible. Also make sure that no stray strands from the negative or positive bus are touching each other in any way, or that they would even be able to touch if the cables were moved.
3) Use a No. 1 Cross Head screwdriver to tighten the terminal block onto the bus wires. Once secured the bus wires should be held firmly in place.
Step 6 – Adding power
1) While this is definitely the most exciting step of the whole process, be sure not to rush and make sure everything you’ve done so far is correct and safe.
2) The first step is to plug your transformer/power supply [Part G] into your desired plug socket – DO NOT turn the socket on yet! Make sure the lead from the transformer comfortably reaches the barrel connector on the end of the bus wires, this connection shouldn’t be under any considerable strain. If it does, you can now insert the barrel plug into the terminal block connector, if not, it is advisable to use a suitable extension cord so that the cable from the transformer isn’t under strain.
3) Now you’ve connected the transformer to the bus wire connector it’s the moment of truth... turn it on at the wall and with a bit of luck your layout will be well on its way to looking great with your new lights!
Assuming everything has worked you are now free to power the system off at the wall, wait at least 15 seconds for the system to fully discharge, then return to Step 2 and continue adding more lights!
If you have any further questions or concerns feel free to get in touch!