Seeing an illuminated model passenger train at night is a magical experience. Installing lights makes the trains seem more alive and presents a project within the building and operating of a layout.
There are many, many ways to illuminate passenger coaches. Some methods are more expensive than others, some are easier to install than others and one can find advantages and disadvantages of every approach.
Each approach is a combination of a number of factors:
- Lighting technology: Incandescent/LED
- Battery or track power
- One, or multiple, power pickup shoes for the train
- Full rectification of half wave rectification
- Approach used for anti-flicker
- Permanently coupled rakes or current conducting couplers
- Off-the-shelf solution or DIY
- Unless one is aiming for a classic toy era style, LED lighting is clearly a no-brainer.
- The high costs of current conducting couplers rules them out for me
- Multiple pickup shoes create too much drag on long trains (and they are not cheap either)
- LED utilizing cheap 12V LED strips.
- Track power to be used
- Single power pickup shoe per train
- Permanently wired conductors run the length of the train
- Full rectification of digital track power
- Capacitor for anti-flicker
- Inrush current limiting
- DC-DC converter used to set brightness
- Twin wires run along the length of the train to each coach
Steps to install whole train lighting
Modern modeling uses Light Emitting Diodes (LEDs) extensively. This is because they offer numerous advantages over older technology, such as incandescent 💡 light bulbs:
- They are small
- They are cheap
- They are long lasting
- They use very little current
- They do not get hot
- They are available in many colors (including 'warm' and 'cool' white)
LED packagesLEDs come in a variety of different forms and sizes (called packages in the electronics industry).
Typically round 2mm, 3mm, 4mm or 5mm. Rectangular and other shapes are also available.
Surface mount (SMT)
These are even smaller than the through-hole packages and are usually soldered directly to circuit boards by machines. One can now also buy them with tiny wires already attached and these are ideal for model building.
The different sizes are expressed using a 4 digit code that is made up from the length and width of the LED in tenths of a millimeter. For example a 2835 is 2.8 mm by 3.5mm. 5050 is 5mm x 5mm. Note however for that some LED sizes are expressed in thousandths of an inch instead, so a 0402 SMD LED is is 1mm x 0.5mm. It is so small, it represents an object 87mm x 43mm in HO scale! - smaller than a lightbulb.
White LEDs are also commonly found in long, flexible strips up to 5m (16') long. These are made using surface mount LEDs. They are pre wired and ready for use with 12V (sometimes 24V). One can cut them to small lengths, typically 5cm long. These are ideal for passenger car and station lighting. They often use 5050 or 3528 sized LEDs. They are available in various colors, including warm, and cool white.
These strips come with a crummy adhesive backing that will not stick for long, and so should be ignored. They need to be attached with a quality double sided tape such as 3M VHB tape.
Multicolor neopixel etc.
There are components that comprise 3 (R,G, B) or 4 (RGB+W) LEDs which allows the color of individual LEDs in a string to be digitally controlled independently. These fall out of scope of these fundamental concepts.
In order to understand how to connect LEDs up we do need some very fundamental understanding of electricity. Specifically we need to know a little bit about voltage, current and resistance. It may aid the understanding of these concepts by thinking of electricity rather like water in a pipe. For this analogy:
- Voltage (V) - think of the Voltage as the pressure/speed of the water in the pipe. Measured in Volts
- Current (I) - think of the Amperage as the diameter of the pipe. Measured in Amperes (Amps, A or mA. 1A = 1000mA)
- Resistance (R) - think of resistance as obstructions to the flow of water in the pipe, such as blockages or mesh grates that slow the water down. Measured in Ohms (Ω)
These three things have a simple relationship between them: V = I x R (Ohm's Law) and this formula is used to calculate things in all circuits, but fear not, most of the calculations have all been done already.
Just like a pipe, where water can travel in both directions, so can electricity flow in either direction along a wire. If the pressure is higher at one end, water will flow to the other end. If the voltage is higher at one end of a wire, electricity will flow to the other end of the wire, so long as it can get out.
Like pipes, larger amounts of current (Amperes) need thicker wires.
Series and parallel
Some years ago I bought some BUSCH backdrops on eBay cheaply. When I decided to add the expansion I realized I could use some of the backdrops to add some depth to the area which is visible from the main station.
At one end I needed to transition from the Faller Obersdorf backdrop, and also pass in front of the electrical breaker box for the house. I had kept the unused piece so it was a no brainer to simply continue with the same product. I glued it directly to the breaker box. I have also constructed a small piece that can be removed in order to open the door of the breaker box. Here you can see the door half open:
The door closed and the removable section in place:
Beyond the breaker box, I have mounted all the backdrops on 1/4" plywood. Some of these pieces needed to be bent into curves so I scored the back with a circular saw. I then attached doubled sided tape to hold them to the concrete wall (previously painted blue).
Onto this curved plywood, I attached BUSCH item 2871 which depicts some distant snow covered mountains.
When I unrolled the next backdrop, I found to my surprise that the content did not match the box (BUSCH 2873), and in fact suited my needs much better - it was in fact BUSCH item 2874 depicting a factory and some multistory urban buildings which would be more suitable for a railyard than the bucolic countryside depicted on the box.
The views from the main station look promising
An overview of the area...
Close inspection showed that when the loco moved slowly, (along the straight part,) its pickup shoe would bridge the outer rail, and get the leading edge onto the studs on the far side, and then the rear end would drop down and land on the crossing running rail. This of course created a solid short circuit. Nasty.
The lower hidden area has 9 storage tracks.
- 7 of the tracks can handle trains 184cm long
- 1 can handle a train of 201cm
- 1 can handle two trains of 330cm, and 322cm, or one that is 6.52m long.
(The purpose of expansion area was to store shortish trains, as I have 8 long storage tracks in my existing hidden station.)
Once the trains have passed through the fiddle yard (or bypassed it) they climb at 2% up towards the turning loop area:
Two tracks come out of the lower level, and on the way to the turning loop they run parallel to the two tracks that will go to the upper section. This area will have scenery, and I have mounted the plywood for the backdrop.
All four tracks then come together to pass behind our water heater where they travel along a curved section with safety barriers.
The turning loop, can hold two trains (261cm and 251cm) or a single 5.12m train The practical limit for trains running through the extension is therefore 5.12m.
The turning loop area is horizontal so I added a bit of a valley and bridge to add some interest:
The rear track against the wall will be covered by a mountain so that one does not see a train track doing a 180° turn. The rear track will be accessible from below via the holes in the plywood.
A backdrop is also planned to go behind the mountain and wrap around to hide part of the water heater.
- For the fiddle yard I decided to use a 13.5 cm stopping area before the turnouts in each track.
- I also decided to use 3 sensors per track (instead of 4), one at each end and one exactly in the middle. This allows the middle sensor to be used as the slow down section in both directions. This approach will save the expense of 18 sensors for the project.
- The new area provides a lot more flexibility in routing trains, so I decided to implement the ability to dispatch trains to a destination, rather than only along specific routes. I can now define an event on the screen that will dispatch any train in a track to a specific destination with a single click. Clicking on any track with a train also lets one pick any destination, or activate specific routes.
- The long tracks that go towards the turning loop do not allow stopping in the direction of the loop. This ensures that a train already booked into, or already in, the loop cannot get trapped there by trains on the incoming tracks. Stopping is permitted on the way out towards the fiddle yard or on the long tracks.
- 24 turnouts have been laid, turnout switches installed, and connected to k83 type modules.
- 44 sensors have been made by isolating sections of track, and connected to s88 type modules, usually via a 36' long Cat-5 cable holding 8 wires, about 200' of cable. (I used cable my dear wife picked up at the dump!)
- About 436 electrical connections made!
- The layout now has about 271m of track!
Earlier report: https://cabin-layout.mixmox.com/2020/03/storage-expansion1.html
Backdrops done: https://cabin-layout.mixmox.com/2020/06/storage-expansion3.html