Lighting of the LS Models NMBS I2 coaches

Original page created on 20/07/2023; last modified on 22/07/2023.

NMBS I2 B11 coach

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:

Path for lighting wires, seen from bellow the chassis

Click on the photo for a closer view.

Path for lighting wires, seen from above the toilet

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:

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.

Drawing of the lighting strip

Realisation

Here are a few aspects of the finished lighting strip.

View of the strip (front)

View of the strip (back)

Notes:

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.

Dimensions for machining the strip stops

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.

Dimensions for drilling the body

Here’s the result of the machining.

Result of machining the body

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…

Soldering a bare wire to the bogie

… 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.

Bogie equipped with its connecting wires

Fitting the strip

The strip is easy to fit. It is held in place by a small ball of Blu-Tack at each end.

Réglette côté LED

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.

Three-quarter view of compartments

Side view of compartment, low angle

Corridor side.

Three-quarter view, corridor side, low angle

Side view of corridor, low angle