# MTH Passenger Car and Caboose stock lighting melting at command voltages



## L0stS0ul (Feb 6, 2015)

I have a lot of the 60 foot MTH passenger cars and Cabooses and as I pull things apart to replace dead bulbs or upgrade to LED I've noticed a very disturbing trend. These things are melting the bulb casings and things around them. Today I opened up one of my cabooses because a bulb had died and I have no choice but to upgrade it to LED. The melting is dangerous and I see it in every car I take apart. I've actually seen melted plastic pooled on the floor of passenger cars.
















Most of the stuff I have is about 10 years old from 2005-2008. Are the passenger cars and cabooses still using this lighting system?


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## Lee Willis (Jan 1, 2014)

I don't know if they still use this lighting. I've had the same problem a few times. I'm Replacing the incand. with LEDs is the best way to assure it will not recur. Installing a resistor would cut the heat generated by the lamp (and the light, too, but if you run at command voltages all the time it would still be sufficient). 
It's cheaper and "faster" in some sense to jury rig a different mounting where you make a new holder for it - I made one out of alum. foil and epoxy that did the trick, just held the thing free in the air, inside a type of reflector. But that's Rube Goldberg and I would not repeat that. 

And I have to say that while I have seen evidence like your photos show, and worse - melted sagging plastic nearby, I never had one go catastrophic and cause a fire or anything, or even spark, etc. They just look bad when you open them up.


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## Spence (Oct 15, 2015)

My solution: don't open them up.


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## gunrunnerjohn (Nov 10, 2010)

The resistor is probably not the best choice, if you want to install something, put in a diode. The resistor just moves the heat from one place to another, the diode will cut the effective power in half for the bulbs. They'll be dimmer, but they'll also be a lot cooler.

Of course, my solution is and will always be an upgrade to LED lighting. It's better in every way IMO.


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## L0stS0ul (Feb 6, 2015)

Thanks for the info. I'll be upgrading this one to LED for certain. Looks like a lot of good places to hide the components in it which is good. This one is not melted too bad but the scorch marks are concerning. 

My k-line cabooses with the streamlighting seem to run a lot cooler at command voltages. Just don't turn on the smoke


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## phillyreading (Aug 25, 2015)

gunrunnerjohn said:


> The resistor is probably not the best choice, if you want to install something, put in a diode. The resistor just moves the heat from one place to another, the diode will cut the effective power in half for the bulbs. They'll be dimmer, but they'll also be a lot cooler.
> 
> Of course, my solution is and will always be an upgrade to LED lighting. It's better in every way IMO.


I am not that good with electronics and names of parts for them. Could you be more specific about what you mean? Like do I install a diode and a resistor or what all would I need to use with an MTH caboose? Like can you give me part numbers and names of the parts to use, please?

I am decent with electrical work, not that good with electronics as it seems to be two different things or areas. If I had the schematic I should be able to follow it.

Lee Fritz


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## Lehigh74 (Sep 25, 2015)

L0stS0ul - What is melted in the photo? Is it the yellow discoloring where the bulb plugs in? I have several Railking 16” passenger cars from 2007, 2010 and 2010 and they all have the same bulb. I use a ZW and set the voltage on max. I just replaced a bunch of bulbs and saw no melting, but I did see some discoloration like you show on the caboose. I also have some Premier 18” passenger cars from 2014 that have a similar bur smaller bulb.


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## gunrunnerjohn (Nov 10, 2010)

Lee, I'm saying to drop the heat and power from the bulbs and the smoke units in the caboose, a simple diode is sufficient. The 1N400x (x is 1 thru 7) will do the trick for a caboose, it's in series with the pickup lead.

Older MTH cars had 12-14V bulbs and would overheat on 18 volts. More modern cars went to 18 volt bulbs and they don't have the same issues. I have a ton of MTH bulbs left over from LED upgrades, and I have both the lower voltage and the 18V ones.


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## Lehigh74 (Sep 25, 2015)

gunrunnerjohn said:


> Older MTH cars had 12-14V bulbs and would overheat on 18 volts. More modern cars went to 18 volt bulbs and they don't have the same issues.


That's good to know. I believe all of mine have the 18V bulbs (PN CI-0000009).


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## L0stS0ul (Feb 6, 2015)

Lehigh74 said:


> L0stS0ul - What is melted in the photo? Is it the yellow discoloring where the bulb plugs in? I have several Railking 16” passenger cars from 2007, 2010 and 2010 and they all have the same bulb. I use a ZW and set the voltage on max. I just replaced a bunch of bulbs and saw no melting, but I did see some discoloration like you show on the caboose. I also have some Premier 18” passenger cars from 2014 that have a similar bur smaller bulb.


It might be hard to see but the clear bracket is melted and warped due to the heat and the discoloration is melted plastic around the bulb. I've already taken the item apart and there is more damage from the heat that is harder to see. I've seen a lot worse than this but this was the one I had as an example. I'm more interested to know if they have changed the lighting for the current crop of cabooses and passenger cars.


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## L0stS0ul (Feb 6, 2015)

gunrunnerjohn said:


> Lee, I'm saying to drop the heat and power from the bulbs and the smoke units in the caboose, a simple diode is sufficient. The 1N400x (x is 1 thru 7) will do the trick for a caboose, it's in series with the pickup lead.
> 
> Older MTH cars had 12-14V bulbs and would overheat on 18 volts. More modern cars went to 18 volt bulbs and they don't have the same issues. I have a ton of MTH bulbs left over from LED upgrades, and I have both the lower voltage and the 18V ones.


How can you tell if you have an 18v or 12v bulb? Most of my stuff is from 2005-2008. This caboose looks to be from 2000 so it is a bit older.


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## pennwest (Sep 21, 2015)

All of my MTH cabooses (including one PRR N5c like the one in the original post) have two light bulbs. I remove the floor of the caboose and rewire the bulbs in series. This dims the bulbs sufficiently so that with the room lights on, the caboose appears almost dark. With the room lights off, the interior is lit but not with the "tanning bed brightness" that they have right out of the box.

Here's the original lighting at my command control track voltage of 16.5:









and here is the series-wired bulbs at the same voltage:


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## pennwest (Sep 21, 2015)

The fix is really easy. Here is the caboose with the floor removed.









In this closeup, you can see the black wires from the pickup rollers and truck wheels coming up from the bottom, the white and gray wires going to the bulbs in the tender and the two black wires (at the top) going to the marker light LED board.









Snip the gray wire going to one of the bulbs and the white wire going to the other bulb.









Connect the white wire to the gray wire, solder and insulate with some heat shrink tubing. Put the caboose back together.


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## hokie71 (Jun 9, 2013)

Another reason to run conventional, I never get above 10-12 volts it seems.


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## L0stS0ul (Feb 6, 2015)

pennwest, that does look like a good option. I'm already down the road of converting mine to LED but I have 2 others that I might give that a try with and see how I like it. Thanks!


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## gunrunnerjohn (Nov 10, 2010)

The diode does the same thing as what *pennwest *shows, drops the voltage of the bulbs in half.


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