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DCC decoder in a OMI locomotive

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DCC decoder in a OMI locomotive
Posted by fondo on Wednesday, March 2, 2011 8:40 AM

Hello everyone, I'm doing my first steps in DCC and I would like to turn my OMI locomotive in DCC. I don't know how to do it, that's why I need you help on the procedure. I've taken photos and I do understand about electricity and using a tester. It would be greatful any comment you can give me or any web page where it explain how to do it.

It's HO scale, and I have the following decoders(if non of the are usefull, please tell me which one can be)

DH121D
DH165IP

Photos




Thanks in advance! :D

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Posted by Paul3 on Wednesday, March 2, 2011 10:40 AM

fondo,
I've done more than a few OMI's, so I've been down that road before.  BTW, only two of your pics show up...the third won't load.

First, have you ever done a hard-wired decoder install before?

Second, do you want working headlights?

Third, are there ditchlights and do you want them to work properly?

Neither decoder will help you if you want ditchlights.  You need a DH163D or DH165D for that.  Otherwise, the DH121D would be okay for this loco if you just want front and back headlights.  The DH163IP has a plug on it, and would be worthless for this OMI engine (unless it has a plug on it for DCC...and I don't thing OMI ever did that).

When installing a decoder, the first thing to do in this case is to unplug the lighting, then remove that PCB (printed circuit board) with all the DC lighting components on it.  IOW, cut all the wires leading to the board from the various lightbulbs, leaving as much wire as possible on the bulbs.

Before doing anything else, mark the underframe to indicate the forward end either with a marker, scribing it, or some tape.

Next, you have to disconnect the wires from the motor, either by cutting them or unsoldering them from the motor.  You may have to pull the motor out to get at the lower soldering pad, or you could try to leave some wire on the motor for a connection later.

At this time, you should also cut the truck wires, leaving as much wire on the trucks as you can.  You'll need them later.  You should now have both trucks totally isolated from each other and the motor, with the motor isolated from anything else.

Get the decoder out, and you'll see it has 9 wires on it: black, red, orange, gray, blue, white, yellow, green and purple (not in that order).  Black & red go to the trucks, orange and gray go to the motor, blue is the common for all lighting, white is for front headlight, yellow is for rear headlight, green is for Function 1 (or F1), and purple is for Function 2 (or F2).

The secret to doing a good hard wire DCC install is to use the least amount of wire to get the job done.  Trying to save all the wire makes it a real bear to get the shell back on.

I usually position the decoder right on the motor top center and tape it in place with 3M Magic Tape as it won't dry out like normal tape will.  At this point, I temporarily wire the decoder in place by merely stripping the wire of the ends of the black, red, orange and gray wires off the decoder, then connecting them to the proper wires on the model. 

Red on the decoder goes to the engineer's side of the engine (or right side), black goes on the fireman's side (or left side).  On your model, it appears that OMI has done the opposite, so red decoder wire to black truck wire and black decoder wire to red truck wire.  You only have to do this for one truck at this time as this is only a test.

Now connect the orange and gray wires to the motor.  I don't know which goes where...that's why we test first.  Make sure all wire connections are not touching anything else, and bring it over to your DCC track.  Put the loco on it with the track power off.  Again, make sure all wire connections are isolated from each other or the model.  Now turn on track power and try to run the engine on address 03.  The loco should run and it should run forward as indicated on your DCC system throttle.  If it runs backwards, then the motor leads need to be reversed.  Which ever way it is, write it down.  Either orange on top and gray on the bottom or vice versa.

Bring it back to the workbench and undo all the wire connections.  At this time, cut to length the orange and gray wires so that they are just long enough to connect to the motor (if you are splicing wires together, use 1/16" heat shrink tubing).  Strip 'em and connect them to the motor as indicated by your test run.

For the truck wires, stretch them towards the other truck and see if they'll connect.  If so, great.  If not, you'll have to add a little piece of wire to them, but don't solder them yet.  Once you've got the front and rear trucks ready for solder, measure, cut, and connect the red and black decoder wires to the nearest connection to the truck wires.  Now solder and insulate the wire connections.

Bring the model back to the test run area, and run it again.  The engine should run forward and back, matching the direction of your DCC throttle.

Lighting is the tricky part.  Each 1.5v bulb will need a resistor.  I usually start with a 680 ohm, but that may be too much or too little.

Start with one bulb, and temporarily connect the blue wire to one leg and a resistor to the other leg of the bulb.  Now connect the white or yellow wire to the resistor.  Bring it over to the DCC test area (making sure all wire connections aren't toucing anything important) and turn on the light.  If it's the brightness you want, great.  Otherwise, you have to play around with different resistors until you get one you like.  Back to the workbench.

What I do is pair up resistors by twisting them together at one end so they are side by side for engines like yours with twin lights (with heat shrink tubing covering the ends).  One bulb wire goes to each resistor end, while the other end of the resistor goes to the blue wire.  The other two bulb wires go to either the white (front) or yellow (rear) wire.  You have to do this twice, once for each end of the loco.  I try to put all this inside the shell, taping it all in place and leaving a long blue, white, and yellow wires so one can get the shell on and off easily.

If you have ditchlights, you have to do the same for them, but with the green and purple wires, one resistor each, plus the other connection to the blue common wire.

Again, test it on the DCC track to make sure it all works, then put the shell on.  One more test, and it should all light up and run.  To program the ditchlights,  program CV49 to 104, CV50 to 104, CV51  to 106, CV52 to 107, CV62 to 196, and CV63 to 64.  This will cause your ditch lights to be on while moving along the track and flash when you press F2 at the crossing.

If you run into a specific problem, please post it.

Good Luck!

Paul A. Cutler III

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Posted by fondo on Wednesday, March 2, 2011 11:20 AM

wow Paul thanks for your answer.

Yes it's my first time doing this so I will have to read and re read what you wrote me. Is there any image that illustrate how to wire everything?

Thanks!

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Posted by Paul3 on Wednesday, March 2, 2011 12:19 PM

There should be a diagram with the decoder, but here's one from the Digitrax website:

http://www.digitrax.com/v1/ftp/ditchlights.pdf

Note that the bulbs used in this example in the pdf file are 12v bulbs while OMI uses 1.5v bulbs.  The OMI bulbs need a resistor to knock down the voltage to acceptable limits, at least with the DH163 and DH123 decoders.  The DH165's may or may not.  I haven't done much with a DH165D yet, but some DH165's seem to have current limiting resistors built in (like the DH165AO, which is a board replacement form factor rather than shrink wrapped).

Paul A. Cutler III

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Posted by Hamltnblue on Wednesday, March 2, 2011 2:48 PM

fondo

Hello everyone, I'm doing my first steps in DCC and I would like to turn my OMI locomotive in DCC. I don't know how to do it, that's why I need you help on the procedure. I've taken photos and I do understand about electricity and using a tester. It would be greatful any comment you can give me or any web page where it explain how to do it.

It's HO scale, and I have the following decoders(if non of the are usefull, please tell me which one can be)

DH121D
DH165IP

Photos

https://lh6.googleusercontent.com/_UsOfXqoxLKo/TW5MrSgK7AI/AAAAAAAAAFY/uNqPz4G6Qaw/s720/IMG_7212.jpg


https://lh4.googleusercontent.com/_UsOfXqoxLKo/TW5MsD7NhPI/AAAAAAAAAFE/kET4XbYAqwI/s720/IMG_7213.jpg


http://s1.postimage.org/g3k2opp5m/IMG_7215.jpg


Thanks in advance! :D

Springfield PA

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Posted by Hamltnblue on Wednesday, March 2, 2011 2:50 PM

his third pic:

http://postimage.org/image/1x4bthe10/

 

Springfield PA

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Posted by richg1998 on Wednesday, March 2, 2011 3:17 PM

Hamltnblue

his third pic:

http://postimage.org/image/1x4bthe10/

 

http://postimage.org/image/1x4bthe10/

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by fondo on Wednesday, March 2, 2011 3:22 PM

Thanks for showing the picture!

Do you think that in can be a start point trying to make work the decoder just for moving the loco and then try with the light?
Also which resistor should I use?

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Posted by Hamltnblue on Wednesday, March 2, 2011 3:28 PM

Take a pic of the other side of that circuit board there.

Also check to make sure that the motor is electrically isolated from the chassis. If it isn't you'll have to insulate it with electric tape.

Springfield PA

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Posted by fondo on Wednesday, March 2, 2011 3:29 PM

how do I check the insolation? I can not take a pice from the other side beceause the cable length doesn't allow to turn it

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Posted by richg1998 on Wednesday, March 2, 2011 3:48 PM

fondo

How do I check the isolation? I cannot take a piece from the other side because the cable length doesn't allow to turn it

 

Use the ohms scale of your multimeter. Trying to do this at this level without a meter will be difficult for those who do not understand electrical.

There should be no electrical path between the frame and either motor contact. I use Kapton tape from Litchfield Station. This is a tough thin tape. Make sure you cannot see any wire from each motor contact touching the frame anywhere.

Below are some useful links about DCC. Take time to read though then as it will enhance your knowledge of DCC.

http://www.mrdccu.com/

http://www.members.optusnet.com.au/nswmn2/DCC.htm

While this will not exactly answer all your questions for this particular loco, you will have a lot fo useful DCC info for the future. There are basic NMRA wire codes for DCC and the info is in those links.

Rich

 

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Posted by Hergy on Wednesday, March 2, 2011 4:54 PM

Based on your questions I think your first step should be to buy the Kalmbach book on DCC and study it. Hardwiring a decoder into a brass loco for your first try is a big and potentially difficult job for your first. The info you have been given thus far, while accurate and probably helpful, I feel may be a bit over your head. Just my perception. Good Luck.

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Posted by richg1998 on Wednesday, March 2, 2011 5:15 PM

Hergy

Based on your questions I think your first step should be to buy the Kalmbach book on DCC and study it. Hardwiring a decoder into a brass loco for your first try is a big and potentially difficult job for your first. The info you have been given thus far, while accurate and probably helpful, I feel may be a bit over your head. Just my perception. Good Luck.

From what I can see, mounting the decoder securely will be a bit of a challenge. No doubt have to make a support shelf over the drive shaft to mount the decoder. I have done something like that in a Spectrum 70 ton but I was able to put  styrene shelf in place for the decoder and a small piece of copper clad PC board to minimize wire splices. I have some Vero board from the UK I picked up some years ago for various electronic projects.

I then followed the instructions that came with the decoder. Many sue 1 k resistors but a few use maybe 2k for ditch lights as they thought with 1k, the lights were too bright but it is your railroad.

Below is what I did for my loco as an idea. I have used this PC board in other loco conversions.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by rrinker on Wednesday, March 2, 2011 9:28 PM

 Of the two decoders you mentioned, the DH121D would work, but not if you want ditch lights along witht he headlights. You'll need a better option - the DH165IP is a decoder designed to plug in to an 8 pin socket, you need to hard wire this one. A suitable DIgitrax decoder that has enough functions to do the ditch lights and all is the DH163D. The TCS T4X would also work - unless you have a rooftop beacon as well at the ditch lights and headlights, in which case you'd need the T6X.

 Bottom line, you need a wired decoder that has enough functions to handle all your lights you wnat to include. Front and rear lights are two functions, ditch lights need another 2 if you want them to flash alternately, and then a rooftop flasher or whatever would be another. Too many choices to list them all.

                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Paul3 on Wednesday, March 2, 2011 9:45 PM

fondo,
If you read my post, that's exactly what I suggested.  You really should make sure the engine runs properly before tackling the lighting.  Once the engine runs, the lighting can be done later or not at all.  Your choice.  But you need the motor done first.  As for which resistor, I usually use a 680 ohm as I said above.

Hamltnblue,
Please don't confuse the guy.  For one thing, the motor itself does not have to be isolated from the frame, only the motor brushes (or contacts) have to be isolated.  Secondly, it's an Overland.  I've yet to see any Overland where the brushes are not isolated, and I've installed DCC in perhaps a couple dozen OMI's.  So fondo, don't worry about it with this engine.

richg1998,
This decoder mount is not structural.  He doesn't need to fabricate a big styrene shelf.  A simple piece of Magic Tape holding the decoder to the top of the motor will work fine as long as the wires don't drag on a flywheel.

If anyone is really concerned, there's a little trick one can do with these OMI's.  The PCB the diodes were on that came with the model makes a great shelf for the decoder.  Strip off all the components that are on the PCB with nippers.  Tape the decoder to the PCB, then screw it on to the shelf bracket.  Viola!  Instant mounting for the DCC decoder.

Paul A. Cutler III

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Posted by fondo on Thursday, March 3, 2011 6:51 AM

Thanks Hergy, richg1998, rrinker, Paul3 for yours replies!

So I will try to get the correct decoder as YES I want ditch light working WITH flash alternately, and what I forgot to say, is which decoder can do this? (DH165d?) and also can have the option to include sound in the future??

I've seen that Digitrax has a sound decoder for AC4400 but for Kato, would you recommend me this sound or better from another brand?(here in Argentina is not so simple to get all brands)

THanks again for your replies...

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Posted by rrinker on Thursday, March 3, 2011 7:26 AM

 If you want a better sound option, Soundtraxx has a Tsunami with the appropriate sounds for the AC4400 and QSI also has one with the proper sounds. Either one will be better overall to the currently available sound files for the DIgitrax decoders. Both are motor plus sound, so it's the only decoder you need. ANd they both have enough function outputs to provide the ditch lights - and if you want they will even work with the horn, so when you blow the horn the ditch lights will start flashing, and kep alternating for a set time afterwards, when they will revert to both just being on - this is how they operate in my part of the US anyway.

                         --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by richg1998 on Thursday, March 3, 2011 7:30 AM

fondo

Thanks Hergy, richg1998, rrinker, Paul3 for yours replies!

So I will try to get the correct decoder as YES I want ditch light working WITH flash alternately, and what I forgot to say, is which decoder can do this? (DH165d?) and also can have the option to include sound in the future??

I've seen that Digitrax has a sound decoder for AC4400 but for Kato, would you recommend me this sound or better from another brand?(here in Argentina is not so simple to get all brands)

THanks again for your replies...

I would contact Litchfield Station for decoders. I do know some in the UK and the EU have bought from this company and they do answer email. Let them know where you live. There are different form factors for decoders. Litchfield pretty much spells out everything.

http://www.litchfieldstation.com/DCC-University/index.htm

Decoder mounting might be different depending on which decoder you are able to purchase.

If you had to build a shelf for say a light board type decoder, there are many different sizes of styrene.

Some decoders come with 12 volt light connections for bulbs and LED's and 1.5 volt connections for 1.5 volt bulbs on the same decoder. As was said, a resistor for the LED. One decoder includes LED connections with the resistors on the decoder.

I use a double sided tape from Litchfield that works very nice and can still remove the decoder if there is a problem.

There are some different ways to do this. Post some photos when the project is done.

RIch

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Posted by fondo on Thursday, March 3, 2011 7:31 AM

Thanks rrinker, but if I want first a decoder just for locomotive fuction which one can be that later I can add sound? or it's better to leave that decoder for another loco and buy sound+decoder together?

Also my shop here, doesn't have the DH165D, just the IP one. Does NCE, TCS have a similar decoder?

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Posted by richg1998 on Thursday, March 3, 2011 8:52 AM

In case you do not have the sites, below are the NCE site and TCS site links. Usually all the specs are shown.

http://www.ncedcc.com/

http://www.tcsdcc.com/public_html/index.php

Again, the Litchfield site will show many different types of decoders with specs even if you do not order from them.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by rrinker on Friday, March 4, 2011 11:11 AM

 If you plan to add the sound later, the best way to do this is probably install a ecoder that has the 9 pin plug on it. You can then later simply unplug the motor decoder and plug in one that does sound and motor - the best sound decoders currently are ones that do both so it's a bit of a waster to use two seperate decoders.

 The TCS T4X has 4 functions, enough for front and rear lights, plus the ditch lights. The T6X is 6 function, in case you also need a rooftop beacon. Later on, you can disconnect the 9 pin plug and plug in a Tsunami (and find a place to put the speaker) and you will now have sound.

                        --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by fondo on Sunday, March 6, 2011 8:34 AM

Thanks to all for posting, I'm still yet searching for a 6 functions decoder in my country without luck. Yesterday I got my NCE Power Cab and tested with emotion Big Smile

One of the decoders I got was the Digitrax with Sound for Kato AC4400, I think it could be a bit more noise but I'm completely satisfied anyway. The model is SDH164K14
I was thinking if this decoder+sound can have the function for ditchlight to flash alternately? as I see that there are alone cables and maybe I could add two more lamps? If this can works and think this can be a great decoder to add to my Overland locomotive, what do you think? Is this possible?

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Posted by rrinker on Sunday, March 6, 2011 11:03 AM

 That decoder has 6 functions, so yes, there are enough to run ditch lights, but the sounds are less than satisfying and some have had operational issues with them, like the loco slowing down when you blow the horn. If you are happy witht he way it sounds, there definitely are enough function connections to do what you want.

 Not sure what brands you may have readily available there, but in addition to the Digitrax and TCS ones, NCE has the D15SRJ which has enough functions for the ditch lights, and you can probably get Lenz fairly easily. The Silver+ decoders have 5 functions, the Gold Series have 4, so those would work.

                        --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by fondo on Sunday, March 6, 2011 2:19 PM

Randy, thanks for you answer! To flash alternately the ditchligths I will have to use the cables that come? if yes, how do I know which one, and what lamp's voltage should I use?

What brand would you recomend me decoder with sound for the AC4400?? I will try to search for videos but I think they are depending on the video's camera quality.

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Posted by fondo on Sunday, March 6, 2011 4:57 PM

I founded this image for wiring the decoder. And this PDF
Also, I've some difficult to understand how to program with my NCE Power Cab the Functions 1 and 2 to make ditch lights flash alternately, any help on this?

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Posted by rrinker on Sunday, March 6, 2011 5:46 PM

 What CVs to program depend on the decoder.

If you use the green and violet with a Digitrax decoder, the CVs are listed in the PDF document. Use the decimal numbers, only ancient Digitrax systems needed hex numbers.

for ditch lights you will either need some micro bulbs to fit, these are usually 1.5 volts and will need a resistor on each one to reduce the voltage. Or use surface mount LEDs. These also need a resistor. You cna buy them with wires already attached since it does take some practice to solder wires to somethign that tiny.  Third option is fiber optics int he actual ditch light castings with bulbs or LEDs inside the body. I recomment LEDs for all lights, they run cool and theoretically will never ever burn out. You'd want a 1K resistor to use with each LED, maybe somethign larger like 2.2K for the ditch lights if they are too bright.

                      --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by fondo on Sunday, March 6, 2011 8:28 PM

Ok, I've just understood how to change the values of the CV's, but what value should I set for F1 / F2 (Functions) for dicht lights flash alternately? and how can I set to press F12(not used, or another F#) to start flashing? (sorry if this are questions are totally from a newbie, but that's what I'm hehe)

 

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Posted by rrinker on Sunday, March 6, 2011 8:48 PM

 The settings listed int eh PDF will make the ditch lights flash when you press F2 - which corresponds to the horn, so if you're using the sound decoder, when you blow the horn the ditch lights will start flashing - exactly as they should. The nitty-gritty is that there is a 'phase a' and 'phase b' for the lighting effects, when A is on, B is off, and vice-versa. So what those settings do is set it so that one ditch light, on the green wire, is phase A, and the other ditch light on the purple wire is on phase B. Labeling the wire colors as a specific function is only a default - another of those CV settings make both the green and purple wires activate when you press F2. Depending on the decoder, you can change which F button turns on which wire in almost any combination you want.

                --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by fondo on Sunday, March 6, 2011 9:14 PM

Great, I've one problem. I removed the shell of the AC4400, and I'm watching the cables and I don't have the blue as shown in the image for common's cable of the lamps, just red, white, brown, violet, green, and yellow. The blue one goes to the capacitor, and also the black one.

Which would be the two cable for each lamp of ditch lights?

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Posted by rrinker on Monday, March 7, 2011 1:22 AM

 Looks like you've hit a serious omission from the manual for this decoder - where the heck are the pads for the extra functions? The wires coming from the 9 pin plug, with 2 already connected to teh speaker adn 2 already connected to the capacitor, are NOT the function wires or the normal hookup for power or the motor, because this is a replacement board for the standard Kato light board. Usually on such decoders there are pads to solder wires to for the extra functions, and one is the equivalent of the blue common wire. But the manual for this one does not show that, nor do any of the similar ones (there are versions for the SD38-2 and F40PH as well - same board but slightly different size to fit the other locos). I did some searching and did not find where this is mentioned anywhere. You may have to call or email DIgitrax about this.

                     --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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