Adding a strobe warning light to my GS-4

What you are referring to is a Mars light not a strobe - the effects are very different. There are a couple of older threads on this forum about adding Mars lights which I think you'll find if you do a search.

There are some Mars light kits on the market, mainly for HO but these are adaptable to O scale engines. Miniatronics makes a good adjustable Mars light kit with incandescent lighting already wired to the control board. There are more specialized effects available from Ngineering using LEDs instead. 

Here are links to the Miniatronics and Ngineering products:

http://www.miniatronics.com/Me...&Product_Count=1

http://www.ngineering.com/lght...20the%20railroad.htm

I have added Mars lights to 3rd Rail engines, including a G4, using Ngineering light effects products. In fact I found that the main problem was getting power to the board that controls the effect. Ngineering however make a DC power source that provides the right current from track power (it has a miniature on-board rectifier) although I ended up wiring this and the control board to the poles on the can motor so that the light only comes on when there is power to the motor.  I never mastered how to make the light flash only when the engine is in forward motion but I like the effect anyway.

Forum sponsor Evan Designs has track powered strobes.

http://www.modeltrainsoftware.com/bl-213-f.html

I think I'll go with the ngineering product.  The low voltage model looks good to me, since I'm currently running analog.  I think I'll use one of the two outputs on the GS-4's built in voltage regulator to power the unit. (it's for the light and smoke) The output remains at 8V DC most of the time.  That should be easy, as I might free up one of the plugs when I change the smoke configuration.  Thanks again!

I guess I wasn't using the correct term... I just found out what I was looking for was a Mars light, so it pulses to look like a rotating light, rather than flashing on and off.  I probably will use flashing LEDs somewhere too, though.

Yeah I put one solid LED and one slow flash LED in the headlight of an F3 that kinda looks like a MARS.  But a flash like the one used on the ETD Truck from MTH would be perfect!

Yeah, it actually looks pretty easy to do, if you use one of the two companies Hancock52 listed.

Agent Cal,

Is yours an original 1989 (brass) GS-4 light/smoke power supply board? I believe the Williams board had a 7805 (5v) regulator, as the Suethe smoke unit was a 5 volt model. 

I'm not entirely sure what year my locomotive was released, but it's the latest model.  I found the voltage regulator under the parts listing on Bachman's website, and it said it was 8V.  In addition to that, I checked the output voltage with a volt meter, and it's 8V DC.  I'm not 100% sure the smoke unit is Seuthe, I can't find it anywhere other than Bachman's website, but everyone says it is, and it sure acts like one.  I adjusted the throttle and everything, it seems to stay a 8V unless I lower the throttle almost to 0.  I guess even if the regulator was 5V, the light unit would still work, since it will go as low as around 2V (or was it 3?)

My Williams E7 has a LED that simulates a MARS Light.  You might be able to order the parts from Bachmann.

OK. You must have the die cast one that looks just like the 8307 Lionel first released in 1983. That engine created quite a sensation in its time. For running characteristics, I'd prefer yours because of its can motor. The current Williams undoubtedly has a different board. Sorry to confuse the issue. 

Do you have a part number or description for that item and any control board used with it? Sorry to ask but after having a look at the Williams spare parts web pages I can't find any E7 LEDs or control boards listed. They do list some LEDs and related parts for HO engines but there's no way of telling whether they can be adapted for O scale. I'd be interested in seeing if it makes for a better/easier way to put Mars lighting in my diesel models.

I use the Ngineering MARS Simulator, it provides a very realistic effect with a single LED.  It's the best solution I've found.

I use the same product but not with an Ngineering LED, instead I use a golden white LED from Evans Designs. It's very bright - bright enough to light a very long stretch of track - but the effect is highly realistic.

Yeah, I just looked up Lionel 8307 (Google Images) and it looks basically like mine, except I think the wheels might be a little smaller.  Also the paint scheme is brighter, the Williams engine has a darker one for some reason.

I'm not entirely sure how to get to that... The Bachman web interface isn't the most user friendly, so I didn't spend too much time, but the parts listing for specific engines doesn't necessarily list all the parts.  I was trying to find a replacement smoker (Seuthe I think) for my GS-4, and it doesn't list the smoker and a few other parts under the parts listing.  After much digging, I found the unit, (Under "order parts">"universal" or something like that, quite a few pages in) which was out of stock.  "Obscure" parts like the smoker or light might not be easy to get to, or even available.  It seems like it would be better to use one of the companies you listed, which you obviously know a good amount about.