Choke:

LEDs are diodes (Light Emitting Diode) but they do not tolerate back voltage very well; it shortens their life. So you put in a regular diode in the same direction, or a bridge, to handle/eliminate the reverse voltage.

The choke is installed to keep the DCS signal from being affected/degraded.

@MCD4x4 posted:

...  I know the board has positive and negative so I'll go with that.

Let's be absolutely clear here.  If you're doing 350 (three-hundred-fifty! ) conversions you need to be sure i's and t's are dotted and crossed!

Are you saying you already have a "board" with some pre-configured circuit?  Tell us more about this "board".

Another reason to install the bridge rectifier and/or diodes is to allow use of a capacitor for flicker reduction.  If this is your first application of LEDs to replace incandescent bulbs you might be surprised in how much inherent flicker reduction bulbs provide since the heated filament can only cool down so fast.  OTOH, LEDs turn off (go dark) instantly when voltage is removed.  Inexpensive capacitors (5 or 10 cents each) restore the flicker tolerance you get for "free" with bulbs...but you need the diode(s) or bridge rectifier.

Resistors, diodes, capacitors, LEDs, etc. for car lighting are a few pennies each.  The overwhelming "cost" of your conversions is time/labor in opening the cars, re-wiring, and so on.

Even the seemingly "exotic" choke is only a nickel...

@MCD4x4 posted:

https://www.quora.com/Why-dont...e-choke-in-led-bulbs

That reference has nothing to do with why we use a 22uh choke for electronic circuits powered by track voltage in model trains.  You need to understand what you're reading and why the statements are made.

The choke we use is to block the DCS signal degradation by any bulk capacitance in the lighting circuit.   It does that by inserting a high impedance to the 3.27mhz DCS carrier in the power lead while allowing the much lower frequency 60hz to pass unimpeded.

The ballast or "choke" they're talking about is really a mis-naming of a simple power supply when talking about LED lighting.  Then they launch into a whole description of florescent bulbs, which has no similarity to LED lighting, and nothing to do with what you're trying to do.

Maybe a plug for my lighting modules would be good here.   I've worked out these problems.

I don't know....maybe flickering lights and lights randomly going out is more prototypical for subway cars?

I've ridden the Chicago 'L' for years and I can tell you; car lighting was anything but constant. Especially when it snowed!

Flickering lights are not welcome on my passenger cars of any type.

@Junior posted:

I don't know....maybe flickering lights and lights randomly going out is more prototypical for subway cars?

I've ridden the Chicago 'L' for years and I can tell you; car lighting was anything but constant. Especially when it snowed!

That's the norm on my layout. My NYC subway cars are all cool white LEDs that do flicker.

On the Septa subway cars the lights used to flicker when the shoes lost contact then recontact while passing over a switch.  Not random, just subject to gaps in the third rail.

John

Thank you for the choke explanation. When everyone gets to talking chokes and FSV, FER or whatever that is in the TIU's, I get glass eyed and a major headache. I do not understand Diodes and all the other electronic stuff (except a capacitor. When I worked for a couple years in the Motor rewind industry we use to take a small motor start up capacitor and connect two thin copper wires to it and tape them down the sides. Charge the capacitor and throw it so someone and yell catch. I learned quick as I was usually the catcher. Talk about a DUMMY. Fell for it several times. Shocking I can tell ya for sure).

Curtis

Well, then you'll be amused with my little "joke" package from years gone by.  I wrapped multiple loops of very fine uninsulated #32 wire around a package and charged up a 450V cap inside and connected it to the alternating strands of wire.  I'd casually hand the box to someone (obviously only touching where there weren't wires), and say "Take a look at this".   The following ruckus was somewhat predictable.

I can not imagine doing a complete package but I can visualize the results. Sitting here laughing and thinking how much fun it use to be.

@stan2004 posted:

Let's be absolutely clear here.  If you're doing 350 (three-hundred-fifty!) conversions you need to be sure i's and t's are dotted and crossed!

Are you saying you already have a "board" with some pre-configured circuit?  Tell us more about this "board".

Another reason to install the bridge rectifier and/or diodes is to allow use of a capacitor for flicker reduction.  If this is your first application of LEDs to replace incandescent bulbs you might be surprised in how much inherent flicker reduction bulbs provide since the heated filament can only cool down so fast.  OTOH, LEDs turn off (go dark) instantly when voltage is removed.  Inexpensive capacitors (5 or 10 cents each) restore the flicker tolerance you get for "free" with bulbs...but you need the diode(s) or bridge rectifier.

Resistors, diodes, capacitors, LEDs, etc. for car lighting are a few pennies each.  The overwhelming "cost" of your conversions is time/labor in opening the cars, re-wiring, and so on.

Even the seemingly "exotic" choke is only a nickel...

Yes sir, at least three hundred fifty cars, that's why I don't want to have to go back for any repairs. I was hoping to put the circuit in for the head and tail lights as I go too, but maybe not. Once I'm done I don't want to go back.

The flickering I'm not very concerned about, I'd actually preferer to have it crossing the switches like it used to do. The few newer models MTH made I'll stop the flickering. Doe the diode and the bridge rectifier do the same thing? It's pretty tight for room in the subway engines, whichever one is smaller would be best.

So to confirm I do need the Choke. which choke is it when I search?

@gunrunnerjohn posted:

That reference has nothing to do with why we use a 22uh choke for electronic circuits powered by track voltage in model trains.  You need to understand what you're reading and why the statements are made.

The choke we use is to block the DCS signal degradation by any bulk capacitance in the lighting circuit.   It does that by inserting a high impedance to the 3.27mhz DCS carrier in the power lead while allowing the much lower frequency 60hz to pass unimpeded.

The ballast or "choke" they're talking about is really a mis-naming of a simple power supply when talking about LED lighting.  Then they launch into a whole description of florescent bulbs, which has no similarity to LED lighting, and nothing to do with what you're trying to do.

Thanks for clearing that up, I'll find the choke parts on line.

@gunrunnerjohn posted:

Maybe a plug for my lighting modules would be good here.   I've worked out these problems.

going that route would be to costly for three hundred fifty plus cars. How are you making out on the last cars head tail light circuit? I'm thinking I need 58 of them.

Well, what I do for tail cars is tap off the LED strip with a resistor and the LED's in series.  I select the resistor to get the desired balance between the markers/tail light and the coach LED strip.  I've also done MTH double-deck SuperLiners with one module and lit the two taillights on those so equipped.

Truthfully, if you really want to do 350 cars, I'd consider making a PCB with a couple extra connections for the marker/tail lights and having the Chinese build them.  You could even add a pot to "tune" the balance between the tail lights and coach illumination.  If you're soldering discrete components together for all those cars, you'll have a lot of time invested.

@gunrunnerjohn posted:

Truthfully, if you really want to do 350 cars, I'd consider making a PCB with a couple extra connections for the marker/tail lights and having the Chinese build them.  You could even add a pot to "tune" the balance between the tail lights and coach illumination.  If you're soldering discrete components together for all those cars, you'll have a lot of time invested.

I wouldn't know how to go about that. The last car head and tail lights, I was referring to the circuit you were working on that would make the headlights go on in the last car when reversing a subway train  

If you look in this OGR post from the Electrical Reference thread, there's a list of DIY circuit board designs including variations of GRJ's lighting board.  It's a long post with dozens of projects so scroll down to project #8

You can save a substantial amount in out-of-pocket cost if willing/able to do the legwork of accumulating parts, soldering, testing, etc.

Note how member Rod posted variations in the size/layout of the bare circuit board which might help fit in the cramped quarters of the powered car.  If you "want" LED flicker you can use a smaller capacitor and save a few pennies per car...and save space.  The choke for this board is the nickel component (when-you-buy 100) I showed in a previous post.

If you have hundreds of intermediate cars to modify (just to convert interior lights from bulb to LED), this will take you quite a bit of time.  In other words, one tack would be to start with the intermediate car modification.  Then perhaps GRJ will be offering a solution to the end-car directional lighting problem.

For anyone else following along wondering what just came out of left field, there was a recent OGR thread about directional lighting in subway consists.

I just haven't had time to get back to the remote control project, and I'm still waiting on some prototype boards trapped somewhere in the USPS black hole.  I decided to push on the MP3 board first and then work on the remote controls.

@MCD4x4 posted:

...

I'm about to start converting 350 Subway cars to LED's. Reading some of the posts here as well as Google searches I'm assuming I don't need a "Choke" when adding the LED lights to both interiors which run off track power or head and tail lights which run off DC from the board. I've also seen bridge rectifiers in some circuits, I tried LED's with 470 ohm resistors for the interior lighting the they work regardless of how which way there soldered up, so why the bridge rectifier?

...

In re-reading your original post, I/we may be getting ahead of ourselves.  I've been thinking/assuming you were going to be using the widely available LED strips that nominally run on 12V DC.

But I now recall you posted photos of the motorized MTH subway cars and looked pretty cramped - and may not be practical to install the LED strips?  So when you say you tried LEDs with 470 Ohm resistors, are you saying you're planning on installing some number of discrete (individual) LEDs in some fashion? 

If flicker is not an issue and if discrete LEDs work best from an installation perspective you can get by with just a resistor or two and the LEDs (no diode, no bridge, no choke, no capacitor).  That is, there is a way to wire up multiple LEDs to eliminate the need for the extra diode.  That is, an LED is itself a diode (albeit light-emitting) so it can do double-duty.  I can expand upon this but didn't want to muddy the waters.

@gunrunnerjohn posted:

I just haven't had time to get back to the remote control project, and I'm still waiting on some prototype boards trapped somewhere in the USPS black hole.  I decided to push on the MP3 board first and then work on the remote controls.

OK, Please let me/us know when you work it out, I can start the lighting in the center four cars not to have to reopen the first and last

@Tom Tee posted:

On the Septa subway cars the lights used to flicker when the shoes lost contact then recontact while passing over a switch.  Not random, just subject to gaps in the third rail.

Out of curiosity, do real subway cars each have their OWN shoes and their own power-conversion system for lighting, heating, etc..  In other words, is there a common power system in some kind of generator car like the Head-End-Power HEP system on Amtrak passenger consists?  Then one might expect ALL cars in a consist to flicker in unison.

And if modifying cars, I can imagine an electrical tether daisy-chain between cars so that the drag-inducing and noisy pickup rollers could be removed.  Then I could better hear the subway announcements..."Next stop, Yankee stadium!"

I recall cars having their own 3rd rail pickup shoes on both sides of the cars. Hot rails would alternate from one side of the track to the other; like over crossings and switches.

And for long trains (6 - 8 cars) during rush hour I think power units were interspersed in the string to provide extra traction. I say that because I remember hearing the "whine" of the traction motors from the middle of the consist as it started up. And since the engineer was always in the lead car; all cars were daisy chained together too.

@stan2004 posted:

Out of curiosity, do real subway cars each have their OWN shoes and their own power-conversion system for lighting, heating, etc..  In other words, is there a common power system in some kind of generator car like the Head-End-Power HEP system on Amtrak passenger consists?  Then one might expect ALL cars in a consist to flicker in unison.

And if modifying cars, I can imagine an electrical tether daisy-chain between cars so that the drag-inducing and noisy pickup rollers could be removed.  Then I could better hear the subway announcements..."Next stop, Yankee stadium!"

Stan,

The NYC Subway cars have a third outside rail shoe, or pick up. The new cars never flicker or go out. The older cars went out when crossing a switch. The third rail is six hundred volts which the motors run on. Everything inside the car is stepped down. I know the older cars a lot of things in the cab were 32 volts.

Right.  I was just trying to imagine a "story" that makes sense for the objective of operating directional lights in the end cars.  GRJ can/will speak for himself on if/when there will be a wireless method from powered car to the end cars.

I was simply suggesting that if the directional lighting is the ultimate goal, perhaps running a 2-wire tether from the powered car to the end car(s) might be an alternative after all.  Or at least something to TRY on one consist since it appears you are fiddling with dozens of subway sets.

Again, the idea here is to simply run a 2-wire daisy-chain car-to-car.  The 2-wire cable simply relays the directional lighting to the end car(s).  There are a wide variety of inexpensive pre-wired male-female 2-wire connector pairs that I think would work.  If the connectors themselves are fastened under the car, you would only "see" a relative thin tether between cars, under black heat-shrink, which would represent the prototype between-car cables.

It's a very low-tech solution in the keep-it-simple mindset.

Sometimes low tech is the best solution Stan.

@stan2004 posted:.

Again, the idea here is to simply run a 2-wire daisy-chain car-to-car.  The 2-wire cable simply relays the directional lighting to the end car(s).  There are a wide variety of inexpensive pre-wired male-female 2-wire connector pairs that I think would work.  If the connectors themselves are fastened under the car, you would only "see" a relative thin tether between cars, under black heat-shrink, which would represent the prototype between-car cables.

It's a very low-tech solution in the keep-it-simple mindset.

I thought of that but the connectors would have to be easier that the ones Lionel used. Those were very hard to get apart. A lot of people ripped them off. Even the ones inside the cars for headlights etc, there to hard to pull apart.

For car to car tethers, I use the Minatronics micro connectors.  Not cheap, but they work well.

@gunrunnerjohn posted:

For car to car tethers, I use the Minatronics micro connectors.  Not cheap, but they work well.

oofah, That would cost 2800 on top of the lighting change over.

With more work, there are plenty of small couplers that will work well.

20 Set Micro JST 1.25 3-Pin Male&Female Connector plug with Wires Cables USA, eBay: 272521449002

$7 shipped for 20 sets, and they're 3-conductor so you have an extra wire for "options".  Just slip some black heatshrink over them to make them less visible between cars.  Lots of other similar options.

@gunrunnerjohn posted:

With more work, there are plenty of small couplers that will work well.

20 Set Micro JST 1.25 3-Pin Male&Female Connector plug with Wires Cables USA, eBay: 272521449002

$7 shipped for 20 sets, and they're 3-conductor so you have an extra wire for "options".  Just slip some black heatshrink over them to make them less visible between cars.  Lots of other similar options.

What do you think about these2 pin at .23 cents each, 3 pin at .30 cents each.  Also would I be correct by assuming I can grab the negative off the chassis?

https://www.amazon.com/Letool%...RZ1CD10S3QD3MXJHDGX3   

They should do as well, and the outside rail "should" be chassis, but if they have run a wire from the truck frame up to the lighting, use that connection, the frame isn't always reliably grounded.

Let's set some "ground" rules so to speak!  Remember this banter is in the spirit of a discussion forum.  Someone show me otherwise, but aside from the Lionel Acela are there ANY other consists that have a daisy-chain tether across more than 2 cars?  Wired or wireless?  So I'm suggesting some work, experimentation, mistakes, mulligans, do-overs, etc. are in order.

Here's what I was imagining...based on eBay listings as shown where you get a pre-wired male-female pair for less than 10 cents.  I was thinking each middle car has a socket-to-socket cable that runs the entire length of the car.  This cable can be fastened to the under-chassis so you don't even need to open the car!  Again, this is the keep-it-simple alternative where the objective is just to get the directional lighting information from the powered car to the end car(s). 

Then, between cars is a plug-to-plug tether to transmit the 2 wires to the next car...but to allow cars to be uncoupled and to allow cars to be facing either direction.  The 2 wires in the plug-to-plug inter-car tether would likely be encased in black heat shrink or whatever to make it look like a prototype power cable.  This tether and extra 1/2" or whatever to allow for bending around curves and what not...again just like the real McCoy.

The powered car and the end cars will have an electrical connection so the daisy-chain enters the interior of the car.  The electronics to "send" and "receive" the directional information would be fairly simple...less than $1 in parts on each end.  And some homework has to be done to accommodate PS2, PS3, etc. lighting.

Separately, if a 3-wire tether is desired.  Then, yes, perhaps something could be done with the interior lights to have all the interior lights across a consist behave together...whether it be basic on/off or flickering in unison (if that's what a prototype did).

And it may well be one has to buy a crimper, loose pins, etc. so as to make exact length cables.  But the point is these tethers should NOT be that expensive...

@stan2004 posted:

Someone show me otherwise, but aside from the Lionel Acela are there ANY other consists that have a daisy-chain tether across more than 2 cars?

Here's what I was imagining...based on eBay listings as shown where you get a pre-wired male-female pair for less than 10 cents.  I was thinking each middle car has a socket-to-socket cable that runs the entire length of the car.  This cable can be fastened to the under-chassis so you don't even need to open the car!  Again, this is the keep-it-simple alternative where the objective is just to get the directional lighting information from the powered car to the end car(s).

Then, between cars is a plug-to-plug tether to transmit the 2 wires to the next car...but to allow cars to be uncoupled and to allow cars to be facing either direction.  The 2 wires in the plug-to-plug inter-car tether would likely be encased in black heat shrink or whatever to make it look like a prototype power cable.  This tether and extra 1/2" or whatever to allow for bending around curves and what not...again just like the real McCoy..

  Then, yes, perhaps something could be done with the interior lights to have all the interior lights across a consist behave together...whether it be basic on/off or flickering in unison (if that's what a prototype did).

Stan, all of the Lionel Subways, three six car sets made all have the the tethering between cars. These cars have opening doors, four sets of two on each side of each car. I would need to run the tether back six cars.

The lighting in subway cars, as far as the flickering when going over a switch, would only be the one car at the moment of crossing the switch. I made this video years ago. This is how it was riding the NYC Subway.

https://youtu.be/MyXOui6ySH4

@MCD4x4 posted:

Stan, all of the Lionel Subways, three six car sets made all have the the tethering between cars. These cars have opening doors, four sets of two on each side of each car. I would need to run the tether back six cars....

Out of curiosity, Lionel did NOT transmit the directional lighting information on the tether - in addition to the door open/close command?  I'm not clear your comment about needing to run a tether six cars for the Lionel Subway.

Again, in the most rudimentary version of the daisy-chain tether, it would ONLY send the tail-light signal from the powered car to the end car(s).  It would not even need to enter the interior of the middle cars...simply mounted underneath the chassis if that makes it easier to install!  There only be "electronics" in the powered car and the end car(s).  The end car electronics would turn on either the headlights or the tail-lights depending on what signal is coming over the tether. 

@stan2004 posted:

Out of curiosity, Lionel did NOT transmit the directional lighting information on the tether - in addition to the door open/close command?  I'm not clear your comment about needing to run a tether six cars for the Lionel Subway.

They did. The directional lighting changes on the rear car to be appropriate when the train changes direction.

Well then.  This kind of raises the stock price of the tether method.  I thought the daisy-chain tether was only used in the high-end (expensive) Acela.  But if Lionel used it in the "bread-and-butter" subways then perhaps there are components, cables, connectors, tiny circuit boards, etc. that can be re-purposed into MTH subways even if only to transmit direction information from powered car to end car(s).

Does anyone have further technical info and/or photos of the Lionel subway daisy-chain method?