Lionel 1862 General light question

[LooseClu]

A neighbor asked if I would look at his 027 Lionel General 4-4-0 which he recently rediscovered while cleaning out his parents house.  The locomotive did not run (and hadn't for 50 years) and a few trim items were missing so I decided I'd restore it for him.  The headlamp was gone but I replaced the lamp shell and want to put a grain of wheat bulb in it.  I tested one such light using the Lionel transformer for power and found it would light the bulb beginning at about one quarter of the full power range.  At full power the bulb was very bright (and warmed rapidly).  I know little about resistors and such but it seems to me I need something on the hot side of that lamp's input to keep the voltage down.  My question: what sized resistor do I need to protect the bulb and the plastic headlamp shell?  The original lamp power circuit was the cause of the loco not running- it was a dead short that had melted a portion of the cab.  Once that was removed and some cleaning and lubrication done, it ran smoothly in both directions.  Now I need to connect the two leads from the lamp to the motor leads and something to reduce the current going to the bulb. 

Roy

 

[lionelsoni]

Just get the correct lamp, which is Lionel's 191-300, rated at 16 volts, 50 milliamperes.  Brasseur, for example, has it for $1.50:  http://www.traindoctor.com/service/lionel/120to250.asp

[sir james I]

It sounds like the bulb your using is 12v, you need a higher rated bulb as stated above, GOW bulbs are made in the 14/16 volt range and no resister would be needed. The bulb will not be as bright though.

[lionelsoni]

In any case, using a resistor to reduce the voltage to a toy-train headlight is problematical.  The power consumed by a low-voltage incandescent lamp in series with a resistor increases up to 82 percent faster for each small increase in voltage, compared with a suitably-rated lamp operated directly from the voltage supply.

[gunrunnerjohn]

If you want to reduce the voltage, I'd be looking at a zener diode, or replacing the light with an LED/Resistor/diode combination.

[cwburfle]

IMHO, if your neighbor's general is a Postwar one in any kind of decent condition, you'd be doing them a disservice to convert it to use a different bulb. On the Postwar generals, the handrail acts as the power feed to send electricity to the bulb. I don't have one out in front of me, but I cannot think of how one could convert the engine to use a different bulb without making modifications to the engine. The correct bulbs are easy to obtain.

[LooseClu]

Thanks to all of you who offered your suggestions.  I would agree that to alter a scale model would not be wise but this is a toy and the original design puts a potentially very hot wire right where a kid would put their fingers to pick the loco up.  I doubt that design would get by the toy division of the present Consumer Protection Agency; I would not want my kid to play with that.  If you turn the engine up side down and look very carefully you can see the one red and one white lead I have added going from under the headlamp into the boiler.  In the open internal area between the electric motor and the weight over the front drivers I have a resistor that drops the voltage to a max of 5v.  and  two small connectors (so you can separate the wires from the lamp to facilitate removal of the cab and boiler from the frame and drive train); these are invisible when the engine is assembled.  I have replaced open frame motors in my HO gauge brass locos with can motors, even added sound to some of them which is sacrilege to many collectors.  I guess I'm already a heretic for those acts now I get to add this 027 loco to that list of evil deeds. Seriously, I understand your point about modifying the prewar locomotive but my choices were rig a light or have no light....I was unable to locate a source for the original lamp base and that handrail was burned through inside the cab 

[gunrunnerjohn]

I think the admonition about "modifying" is a bit over the top here.  First off, you're not making any permanent changes that couldn't be reversed if this is discovered to be a priceless family heirloom.  We're putting a light in a toy!

 

 

 

[Rick NJ]

The Lionel Service Manual explains that the reason for the handrail melting the plastic of the cab was if the front truck derailed, there was an exposed screw that would short to the ground rail.  If track power was not shut off immediately, the handrail would quickly heat up and melt the plastic.  Most of the time I advocate restoring Lionel trains as close as possible to how they were made originally.  In this case, since the original, correct, low wattage bulb is still available, I would recommend to use the correct bulb.  However we could improve on the original Lionel design by running two separate power and ground wires, to prevent the above mentioned handrail overheating and cab melting scenario.