Original page created on 20/07/2023; updated on 22/07/2023.
LS Models NMBS I2 coach.
Preliminary observation
The bogie on the 2-point bearing end is rubbing a little when pivoting.
The roof is easy to remove. There is space for a lighting strip. It measures 232 × 9.6 mm and stops before the platforms. I’m used to lighting them too, so there’s no reason to neglect them, even if the manufacturers do. The maximum available length between the end walls is 250 mm.
There are a few features worth noting:
- the coach comes with pick-up strips. The disadvantage is that they require the brake equipment on the bogies to be dismantled in order to be fitted, as with the I4 coaches, except that here there is no mention of this. This removal is far from easy and risk-free;
- Holes run obliquely through the chassis and into the toilets for the wires to pass through:
Click on the photo for a closer view.
- There are no fittings such as washbasins or toilet seats in the toilets. So there's plenty of room for the lighting capacitors.
The last two points mean that only a minimum of machining is required to install the lighting, which is rare and good.
Lighting strip
Designing the lighting strip
To design the lighting strip, we need to take a few measurements. The pitch of the windows, which will correspond to the pitch of the LEDs, is:
- from the access door to the toilet window: 14.0 mm;
- from the toilet window to the first compartment: 14.8 mm;
- between compartments: 18.4 mm (10 intervals).
The space for the lighting strip is centred on the compartments, not on the axis of the coach. This must be taken into account for toilets and platforms.
Once the strip had been designed in KiCad, I printed out the underside (the LED side) for checking. This enabled me to see that a few adjustments needed to be made. In particular, LEDs H5 and H11 (see layout plan) had to be moved 1 mm out of their nominal position because of the presence of crosspieces that would otherwise have had to be milled. It’s strange that this kind of blunder can still be found on recent equipment.
Realisation
Here are a few aspects of the finished lighting strip.
Notes:
- As a minimum of five PCBs are supplied, I have three bare strips left. This is for amateurs, knowing that these circuits only work in DCC.
- A PDF document containing the layout plan, the list of components and the body machining is available.
Preparing the body
To enable the strip to extend over the platforms, the cross-section of the end supports is milled to a depth of 1.5 mm.
A ⌀ 3 mm hole is drilled 7 mm from the end wall, in line with the coach, to allow the LED to illuminate the access platform.
Here’s the result of the machining.
Click on the photo for a closer view.
Electrifying the bogies
As noted in the preamble, the current pick-up strips supplied are hardly usable. So I choose to use bare wire wrapped around the axle shafts.
There isn’t enough room on the top of the bogies to stick the self-adhesive copper pieces used for the electrical connections, as the passage of the bearing supports doesn’t allow this. So the copper is stuck underneath, although this is less discreet. As usual, 15/100 mm diameter bare wires are soldered onto these copper pads…
… then wound onto the axles. The insulated connecting wires (around 100 mm long, but 80 mm would be enough) are soldered in turn and then run through the oblique passages seen above.
Fitting the strip
The strip is easy to fit. It is held in place by a small ball of Blu-Tack at each end.
Hover the mouse over the picture to see more details.
There are pads at the end of the strip for connecting tail light LEDs, as well as the latching reed switch to control them. I haven’t fitted this device yet, especially as there’s no discreet place for it, as the doors are flush with the end walls.
Result
Compartment side.
Corridor side.
