MU LM-3S and LM-2

[ON28]

Are there any issues consisting a loco with an LM-3S and another with an LM -2? Separately, do I have to add resistors if I swap out bulbs for LEDs with either the LM-3 or -2, or are they configured to accommodate LEDs without a resistor? Thanks!

[nodcc4me]

As long as you set the maximum current for both locos there should be no consist conflicts.


If you are replacing older incandescent  bulbs with led’s you will need resistors.

[KPack]

What Al said.

Any LM will MU just fine with any other.  I have LM-1, LM-2, and LM-3 modules and all play well together.

Yes, you need resistors for LED's.  I use 1/4 watt, 1000 Ohm resistors for my LEDs.

[ON28]

Thanks for that. Maybe something for Tim to consider with all the locos factory-equipped with LEDs.

[Alan]

Thanks for that. Maybe something for Tim to consider with all the locos factory-equipped with LEDs.

Double-edged sword. How would one go about "un-resistoring" an LM if they are using lamps? It's easy to drop the current, challenging to up it.

[nodcc4me]

How about a transistor? I’m trying to think of a reason to raise the current for lamps. 

[TwinStar]

Thanks for that. Maybe something for Tim to consider with all the locos factory-equipped with LEDs.

I don't use LED's. I model the 1960's and the LED lights just don't look right. An incandescent bulb to me better matches the prototype.

[ON28]

On the left is my r/c battery (not RP) Stewart F3 with warm white LED headlight. Looks good to me.

[Alan]

The F3 headlight does look good.

There is considerable spectral difference between LEDs and incandescent lamps so one will never look like the other. Whether or not either is good enough is a personal choice.

Here is a good explanation of the differences in light output: https://www.comsol.com/blogs/calculating-the-emission-spectra-from-common-light-sources/. The graphs make it obvious they are two very different light making animals.

[TwinStar]

On the left is my r/c battery (not RP) Stewart F3 with warm white LED headlight. Looks good to me.

That is a good looking light. Does it have the 'hard' LED on/off characteristics or does it soft light like a bulb? 

[TwinStar]

The F3 headlight does look good.

There is considerable spectral difference between LEDs and incandescent lamps so one will never look like the other. Whether or not either is good enough is a personal choice.

Here is a good explanation of the differences in light output: https://www.comsol.com/blogs/calculating-the-emission-spectra-from-common-light-sources/. The graphs make it obvious they are two very different light making animals.

I was sitting opposite a FedEx 767 today in DFW and their taxi light was a bulb. It had a 1 second off to on time lapse and then 2-3 second on to off time lapse. Our newer Airbi have LED's and it's an instant on/off whereas the older Airbi have bulbs and softer on/off cycles.

[Alan]

I was sitting opposite a FedEx 767 today in DFW and their taxi light was a bulb. It had a 1 second off to on time lapse and then 2-3 second on to off time lapse. Our newer Airbi have LED's and it's an instant on/off whereas the older Airbi have bulbs and softer on/off cycles.

That filament is really hot. Takes it a while to cool down enough to quit producing light. I notice the same rapid-on / rapid-off with late model car taillights and turn signals.

In high school a buddy of mine installed aircraft landing lights in place of his high beams. (For you youngsters, car headlights used to be interchangeable round sealed beam bulbs) The rated operating life of the aviation bulbs was really short and sure enough they burned out rather quickly. But dang, they were bright. Lit up the road for a mile ahead. We used to joke he could blister the paint off of any car in front of him. The adventure didn't end well. Eventually he melted the headlight wiring harness.

[TwinStar]

I was sitting opposite a FedEx 767 today in DFW and their taxi light was a bulb. It had a 1 second off to on time lapse and then 2-3 second on to off time lapse. Our newer Airbi have LED's and it's an instant on/off whereas the older Airbi have bulbs and softer on/off cycles.

That filament is really hot. Takes it a while to cool down enough to quit producing light. I notice the same rapid-on / rapid-off with late model car taillights and turn signals.

In high school a buddy of mine installed aircraft landing lights in place of his high beams. (For you youngsters, car headlights used to be interchangeable round sealed beam bulbs) The rated operating life of the aviation bulbs was really short and sure enough they burned out rather quickly. But dang, they were bright. Lit up the road for a mile ahead. We used to joke he could blister the paint off of any car in front of him. The adventure didn't end well. Eventually he melted the headlight wiring harness.

Aircraft lights and a train horn would sure clear the way!

As bright as the av bulbs are the new LED's are even more so. I much prefer the LED's at work because they will sure light up some real estate.

FedEx approaches runway 35L (east side northbound departures) from the other side than we do so I just happened to get to see this head-on as they were crossing 35C.

A disadvantage to LED's is their rapid on/off cycle. To push back the A320 series the ground crew will install a pin in the nose gear that disconnects it from aircraft control allowing them to push the airplane via the nose wheel. After push is complete they have to show me that the pin has been removed by holding it up. We wave them off with a salute and a flash of the taxi light. With the bulbs a quick flick of the switch will barely illuminate the light and not blind them. With the LED's they get blinded no matter how fast I flip the switch. Our ground crews are now in the habit of walking away with their backs towards us and holding the pin (and attached flag) over their head and waiting for the flood of light to wash over them.

[Alan]

Newer is not always better! At least not in all situations. Awhile back read something about LED traffic signals obscured during a blizzard by built up blown snow because they didn't make enough heat to melt it away fast like the incandescent did.

[TwinStar]

Newer is not always better! At least not in all situations. Awhile back read something about LED traffic signals obscured during a blizzard by built up blown snow because they didn't make enough heat to melt it away fast like the incandescent did.

Funny you mention that. I flew with a guy years ago who was crowd funding money to patent a heating device that kept snow from accumulating on the blue taxi edge lights that had been converted to LED's. As you stated, the heat they generated used to keep them clear in most situations and the 'upgrade' to LED's was missing a critical element in winter.