In my opinion, I can see that Bachmann wanted to go with orange and yellow lights on the K-27 because they would look more like incadecent lights, but I think they went too far. Colors in 1:1 scale don't look the same in smaller scales. So I've replaced the yellow/orange LEDs in the classification lights based on info provided by Dave.
Now that those are a more sunny white, the front headlight seems quite off now. So I was going to replace that one as well but I can't figure out how to get to it. The parts diagram show multiple parts but I can't find a seam to pull it apart. I tried popping off the front lens but it won't give easy and I'll most likely break it, so I was wondering if anyone knows an easy way to access the LED?
I was able to wiggle the headlight wing braces from the platform, didn't have to cut anything. Then unsoldered the wires for the LED on the circuit board behind the smoke box. This allowed me to have easy access to the underside of the head light and get a jeweler screwdriver in the hole where the light wires run. I pushed on the back of the reflector through the hole. Just when I was sure I was going to break something the lens and reflector popped out, just like you said!
The rear light was much easier as it comes apart in several pieces.
Oh, only problem was I bought a 5mm LED because that's what the Bachmann diagram had, and it was, however, the one I bought was flared at the bottom and the original was not, so I couldn't get the 5MM in far enough to get the lens back on. I thought about grinding the flared bottom of the replacement down, but had a 3MM and used that instead.
Al, I'm not sure about shorted headlight wires, but my head light and rear light were on in both directions (so the lights worked but non-directional). Is that what you mean by shorted, or something else? Anyway, I've since converted to DCC and no longer have that problem. In converting to DCC there were a couple of traces and capacitors that I cut out on the existing circuit board, so I assume cutting that fixed the non-directional lights as they are now working directionally. However, if you are not converting to DCC or battery I would not cut these out as those are what makes the headlights work in DC.