Bachmann (Shay) LED bulb?

[Greg Elmassian]

That test is marginal if you don't run anything bigger than a critter.... I run trains that pull several amps, some up to 10.

Your test would not isolate anything but an almost completely failed joint. That motor is probably drawing 1/2 amp or less.

If you don't want noticeable drop in speed, you should really test at double the current the actual train draws. A noticeable slowing can be observed with as little as 1-2 volts "lost".

Greg

 

[Rhinochugger]

Hah! Guess that is fine if you don't run anything bigger than a critter.... I run trains that pull several amps, some up to 10.

Your test would not isolate anything but an almost completely failed joint. That motor is probably drawing 1/2 amp or less.

If you don't want noticeable drop in speed, you should really test at double the current the actual train draws. No offense, but if you are not pulling my led, I see why you are battery power now.

Greg

Yep, you're dead right, my only track powered locos are very low current, so I'm not looking for voltage drop as you say, I'm looking for no voltage - also due to the way I've supplied the power to my track, I only need to go testing in this manner when I suspect a problem which is probably once every two or three years. I have a roughly 300 ft circle with a second feed halfway round, which means that the current only has to go 75ft from each feed before it meets itself coming from the other feed; thus I only notice a problem if there's a real dud.

The battery power is a different issue, more to do with the perennial issue of track cleanliness. My track powered locos are all multi-wheelers; 2-8-0s or 4-6-0s with current collection via the tender wheels as well. Anything shorter is now battery powered, and that also provides an opportunity to run trains at the drop of a hat without any track prep.

I think if I hadn't gone narrow gauge in the early stages, I could have been tempted with the standard gauge, and would definitely have ended up with some two or three loco lash-ups and then it might have been a very different story.

 

[Greg Elmassian]

Yes, as an aside, I grappled with scale/size/NG/STD gauge in the beginning. My personal experiences were on a Class 1 railroad, and was always impressed with multiple lashups, so that put me on the standard gauge route, and then I had to agonize for a while between 1:32 and 1:29, but the much lower cost 1:29 made a lot more sense at the time (and still does)... When I moved and realized I would have a 3.5% grade on the main line, that's where high current and multiple locos really came into play.

Greg

 

[Dan]

I would assume that Bachmann may have used a 10ma led. they used to cost less $$.

 

[Greg Elmassian]

Yep, the days of 20 ma LEDs seems over..

 

[DGE-Railroad]

Just to feed back to the thread, I opted for some pre-wired warm white LEDs which seem to have done the job perfectly.

I worked on the assumption that some resistor-equipped ones would not only save me some soldering but it'd be safer to assume I'd need one than to rely on the PCB

They're a good match for the existing headlight LED. I also put an led grain of rice bulb in the cabin as that was missing too.

The picture is before wiring in the rear light by the way - I'm not leaving the wiring like that!
Two little annoyances ticked off. Now it's just a case of making a decent coal load!