IM SD40-2 Ditch Lighting

[AKNscale]

So yesterday I finally decided to get started on the ditch lighting project. I made an aggravating mistake which basically allowed me no progress, but it gave me the opportunity to show y'all what not to do, lol.

What I did was remove the light pipes with the intention of adding an LED to one of them to get the alternate flashing. However I quickly realized that getting them back in their slot was extremely difficult and I ended up disassembling the body to make it happen. Of course IM glued everything together.... But, with careful finagling and the smallest flathead I have, I got it apart and reassembled safely. Here are the pics:

Here's the body, which was the first part separated. I chose to leave the front handrails on because they were much easier(safer) to separate from the side sill than the body:


This is the front cover for the light tubes on the side sill. I had to be very careful when separating it so as not to damage the the railing attached to the front of the sill:


And here's the front of the sill where the light tubes go in, the white streaks basically show where they sit:


It was a waste of time but at least I could pass on a little knowledge. I'll be working on it again today, but it's snowing here again so I'm gonna have to do some work around the house before I get back to it.

[jdcolombo]

Sometimes, knowing what NOT to do is just as helpful as knowing what to do .

I looked at the shell of mine, and my thought was to cut the light pipes about halfway back from where they terminate at the decoder board on the flat part of the underside of the low hood part of the shell.  Then I though I could glue a 603-size LED at the cut end of each pipe (glued onto the underside of the low-hood part of the shell).  To keep light from one pipe entering the other, paint the pipes flat black, with a tiny piece of black electrical tape over the LED where it contacts the now-cut pipe.  Use 34-38 gauge wire on the LEDs back to the Aux1 (front ditch light) LED and Aux2 (rear ditch light) LED pads, solder, test, put shell on, done.  The only real question is whether the 603 LED would be to high for the shell to seat properly, but I don't think so - it really isn't much "thicker" than the light pipe itself.

BTW, the sound file for the EMD645E3 prime mover on the ESU web site already has the ditch lights set up to alternate when blowing the horn.  If you have a LokProgrammer, you can just install this file over the existing file, and the ditch lights will be set up to turn on with F6 and alternate blinking when F2 is pressed.

John C.

[AKNscale]

My thinking was exactly as yours is, but my decision is to only add one LED to one side and see how it goes. If the results weren't to my liking I was going to add the second. I was also thinking of mounting the LED where the light pipe curves up, that way there will be no chance of the LED getting in the way of the shell fitment. That's the plan anyways, so we'll see how it goes.

[AKNscale]

Did a little more work to it today. I decided that cutting the light pipe and then trying to glue to it would be difficult with the shell together, so I took it apart and removed the light pipe I'm going to customize.


Here's the light pipe I cut. I trimmed it right after it rolls up towards it's original mounting spot:


This is the LED I'm using:


This is how I'm attaching the LED. I'm doing it this way so that I don't have to worry about the LED preventing the body from seating properly:

I'm still using Krystal Klear because I've not got a chance to get anything else that dries quicker.

More updates to come tomorrow. I should be working on the board then.

[AKNscale]

Ok, got some more done earlier. First, I got the LED sealed on the light pipe since the Krystal Klear was dried:


Then got it installed into the side sill:


I then decided it was time to start on the board. First, I got it programmed to operate how I wanted it to. Then I removed the rear lower LED(AUX2):


Then I used some scrap magnet wire from my last install to run the power for the ditch light LED.
Here's the underside:

Here's the board from the top:


Next I'll probably assemble the body then finish the wiring to see how it looks!

[AKNscale]

Ok, got it finished. I assembled the body, and here's how the light pipes are sitting:

The LED is pinned all the way to the left in that groove. It fit in there tight, which works out perfectly because it's now firmly held in place.

Then I connected the board extension harness to the LED wires:


I then assembled it and it works beautifully!(hopefully this video uploads)
Final notes and video coming shortly.

[mu26aeh]

So are you using the rear pad for the new LED for one side, and the existing front pad LED for the other side ?

[AKNscale]

Yes I did, I'm going to do the other side though as the light difference is just too much to leave it as it is.

[AKNscale]

The video uploaded!

[jdcolombo]

Excellent.

I'll probably end up doing this in my unit, once I'm done playing around with speakers and finding the common negative connection for an external keep alive (I'm sending my decoder to Peteski for professional help on that ).

John C.

[AKNscale]

Sweet, I'd recommend doing both lights though. I'm going to work on that tonight.
This is how they look now at a stand still, lol:


I'm waiting for that too, or ESU to get the schematic....

[peteski]

I'm surprised that instead of molding light conduits out of clear plastic IM decided to use plastic fiber optics with (heat-shaped?) sharp 90 degree bends.  Making sharp bends in fiber optic filaments results in light loss at every bend.

[tehachapifan]

I'm surprised that instead of molding light conduits out of clear plastic IM decided to use plastic fiber optics with (heat-shaped?) sharp 90 degree bends.  Making sharp bends in fiber optic filaments results in light loss at every bend.

And light tubes with sharp 90 degree bends (actual corners in some) seem to be becoming more and more common in N scale locos. Interesting how one of the very first (the first?) N scale locos to have lighted ditchlights via light tubes (Kato 9-44CW) were perhaps the brightest. Sure, they were pilot-mount lights which eliminates up to two bends for above-deck lights, but it would appear that model's light tube system was engineered with maximum brightness in-mind....even while still using a standard board-mount LED all the way up in the cab.

[peteski]

And light tubes with sharp 90 degree bends (actual corners in some) seem to be becoming more and more common in N scale locos. Interesting how one of the very first (the first?) N scale locos to have lighted ditchlights via light tubes (Kato 9-44CW) were perhaps the brightest. Sure, they were pilot-mount lights which eliminates up to two bends for above-deck lights, but it would appear that model's light tube system was engineered with maximum brightness in-mind....even while still using a standard board-mount LED all the way up in the cab.

Kato "light conduits" are not fiber optic fibers (like IM uses).  They are injection molded clear plastic parts. They use gentle sweeping curves but where a 90 deg. bend is needed then have a flat 45 degree surface molded on the outside of the bend which bounces the ligtht.  This type of "light conduits" have been used in model locomotives for decades.  But that is not the same as sharply bent fiber optic fibers.

[tehachapifan]

My main point was about sharp bends...which the C44-9W does not have.