News:

Please read the Forum Code of Conduct   >>Click Here <<

Main Menu

Figure-8 reverse loop in DC

Started by H5subway, October 23, 2020, 11:26:07 PM

Previous topic - Next topic

jward

DCC autoreversers only work for DCC.

DCC decoder addresses are not assigned by the controller, they are programmed in by the user with address 3 being the factory default in most cases.


From your original post it appears neither of your sets is actually DCC. You would need to add a decoder to run them with DCC. You would also need a DCC command station, which apparently you don't have. This is a good thing, as you can look for a full featured entry level set (They run under $250) that is capable of not only running your train but programming them as well. Avoid those sets that will only run the trains and change the decoder address, they cost almost as much as one that will do everything.

I could help you with your layout wiring if only i could see your plan.
Jeffery S Ward Sr
Pittsburgh, PA

rich1998

To the OP. A picture is worth a thousand words I learned many years ago. Solves issues faster.

Please sign your name. It is appropriate.

Rich

WoundedBear

Quote from: rich1998 on October 27, 2020, 10:55:14 AM
To the OP. A picture is worth a thousand words I learned many years ago. Solves issues faster.

Please sign your name. It is appropriate.

Rich

Don't worry about your name. If you are not comfortable using your name then don't.

Rich.....please quit making up rules of conduct. If you wanna use your name, go ahead. Nothing here says it is "appropriate" .

WoundedBear

H5subway

Quote from: jward on October 27, 2020, 05:39:55 AM
DCC autoreversers only work for DCC.

DCC decoder addresses are not assigned by the controller, they are programmed in by the user with address 3 being the factory default in most cases.


From your original post it appears neither of your sets is actually DCC. You would need to add a decoder to run them with DCC. You would also need a DCC command station, which apparently you don't have. This is a good thing, as you can look for a full featured entry level set (They run under $250) that is capable of not only running your train but programming them as well. Avoid those sets that will only run the trains and change the decoder address, they cost almost as much as one that will do everything.

I could help you with your layout wiring if only i could see your plan.

Thank you for your advice. Since I'm using Bachmann's controller and EZ track, I was thinking of possibly getting Bachmann's EZ command DCC controller. I watched a couple of tutorials on Youtube about how it works, and it seems relatively easy (like you mentioned, DCC-equipped trains are preset to 3, and an analog train would be preset to 10, and it also explained to how reassign the numbers), so I would be able to run both trains even if one of them isn't DCC equipped. Unfortunately, the tutorial also said that the autoreverser I have won't work for a non-DCC train even if it's running on a DCC system, so I guess that rules out that possibility. So the only option for a DC layout is a DPDT switch? I've uploaded my layout diagram in the original post, but if it still doesn't show up I've also uploaded it here: https://cptdb.ca/uploads/monthly_2020_10/420403057_Newlayout.jpg.1352727b27bcd6d61829a2ba913a33f6.jpg

jward

I looked up the MTH R21 subway cars. According to MTH catalog, these are DCC ready with a 7 pin socket (???) which seems a bit bizarre to me. The standard NMRA socket is 8 pins, and a JST plug which is sometimes also used, is 9 pins. Honestly i don't know where you'd find a decoder that will plug into a 7 pin socket.

The Rail Chief set comes with a GP40, which NCE makes a drop in replacement decoder for )Bach-DSL) but you'd have to hard wire it. Do you have basic soldering skills? I am assuming you do not.

So, DCC will be out of the question for now.

You have insulated the reversing loop part of the layout correctly. To run it on DC all you have to do now is add a DPDT switch to control direction in this section. These can be found in any auto parts store. If you flip the switch over there should be 6 contacts in a 3x2 configuration. Start by connecting a wire between opposite corners of the switch. When you are done you should have the corners wired in an X, with two seperate wires insulated from each other. Next, wire the two contacts on the end of the switch (either end will do) to your controller. Wire the center two contacts to the reversing section. In your case, you have two seperate reversing sections that cross each other you you'll have to run wires to both.

TO operate the reversing section, you first run your train into the section. If it stops at the entrance to the section, flip the DPDT switch. Once your locomotive is fully within the section, flip the DPDT and the reverse switch on your controller at the same time. You can then exit the section and your train will be travelling around the layout in the opposite direction.

If you feel ready to tackle the decoder installations for DCC and want to purchase a DCC command station, you will want to look beyond the EZ COmmand system. It is very limited in what it can do, FUll featured entry level systems with much greater current ratings are available for maybe $25-30 more than the EZ Command lists for.

If you DO go DCC, be aware that while certain DCC systems can run DC locomotives, it is not advisable to do so. The DCC wave form can easily overheat and damage a DC motor not protected by a decoder. This is especially true if the locomotive is sitting still.

Jeffery S Ward Sr
Pittsburgh, PA

H5subway

Quote from: jward on October 29, 2020, 09:44:47 AM
Next, wire the two contacts on the end of the switch (either end will do) to your controller.

Do you mean connecting it to the mainline track, or the DC controller itself? The controller I'm using only has 2 outlets (to connect to the wall plug and the track) so I can't plug another wire into it. The only option would be to plug it into the rerailer terminal on the other side from where the controller is plugged in, but I'm not sure how that would work. However, looking at this diagram (https://www.heathcote-electronics.co.uk/images-reverse-loop/reverse-loop-dpdt.jpg ) it looks like I would simply need to connect the DPDT switch to the mainline track and the reverse loop.

Quote from: jward on October 29, 2020, 09:44:47 AM
TO operate the reversing section, you first run your train into the section. If it stops at the entrance to the section, flip the DPDT switch. Once your locomotive is fully within the section, flip the DPDT and the reverse switch on your controller at the same time. You can then exit the section and your train will be travelling around the layout in the opposite direction.

So unlike a DCC autoreverse module, the DPDT switch can only flip the polarity of the reverse loop, but not of the mainline track without reversing the switch on the controller?

Trainman203

Hooo-boy.  Glad all I have is a point to point.  😮😬🥵

jward

Quote from: H5subway on October 30, 2020, 07:08:59 PM
Quote from: jward on October 29, 2020, 09:44:47 AM
Next, wire the two contacts on the end of the switch (either end will do) to your controller.

Do you mean connecting it to the mainline track, or the DC controller itself? The controller I'm using only has 2 outlets (to connect to the wall plug and the track) so I can't plug another wire into it. The only option would be to plug it into the rerailer terminal on the other side from where the controller is plugged in, but I'm not sure how that would work. However, looking at this diagram (https://www.heathcote-electronics.co.uk/images-reverse-loop/reverse-loop-dpdt.jpg ) it looks like I would simply need to connect the DPDT switch to the mainline track and the reverse loop.

Quote from: jward on October 29, 2020, 09:44:47 AM
TO operate the reversing section, you first run your train into the section. If it stops at the entrance to the section, flip the DPDT switch. Once your locomotive is fully within the section, flip the DPDT and the reverse switch on your controller at the same time. You can then exit the section and your train will be travelling around the layout in the opposite direction.

So unlike a DCC autoreverse module, the DPDT switch can only flip the polarity of the reverse loop, but not of the mainline track without reversing the switch on the controller?

To answer your questions. First, it would be better to connect the DPDT directly to the controller. At some point you're going to have to modify the plug n play wiring and this is one place to do it. It's pretty easy to do with a couple of pan head screws that you screw into your benchwork. You cut your Bachmann plug wire in half, strip the ends and tighten them under your two pan head screws. next, run the two wires from the DPDT switch to the screws and tighten those under as well.

As for the set up, yes, you have seperate reversing switches for the reversing sections and the main line. Ideally they should be on seperate circuits but it's much simpler to use the direction switch already on the controller. The problem is that instead of the reveresing switches being in parallel they are in series, which means that while you are in the reversing section flipping only one switch will reverse the train's direction. To keep it moving forward you must flip both. Once you are back on the mainline, the DPDT switch has no effect on your train and you can run using only the direction switch on the controller.
Jeffery S Ward Sr
Pittsburgh, PA

jward

Quote from: Trainman203 on October 30, 2020, 08:43:38 PM
Hooo-boy.  Glad all I have is a point to point.  😮😬🥵

Does wiring scare you?
Jeffery S Ward Sr
Pittsburgh, PA

Trainman203

No.  I'd rather run a railroad than be an electrician.

jward

You don't need to be an electrician to wire a DC layout. You just have to approach it logically. There are only 3 basic circuits used, and these are repeated as needed. These are 1. regular block, 2. reversing block, 3. switch motor. Even the most complex layout can be wired using just these three circuits.
Jeffery S Ward Sr
Pittsburgh, PA

Trainman203

I'm DCC.  2 wires to the track.  That's it.  Total wiring time- 1 minute 8 seconds.  Then railroading commenced.

I don't like carpentry either.  Not since a skil saw bucked back on me and nearly took my finger off.  I have built a carpentry-free layout.  Well, ok, one saw cut and the lumber yard did it for me.

H5subway

So last week I got 2 DPDT switches and some wires, and was able to make my layout operational (of course, since the polarity has to be switched manually, trains can't just run through the crossover seamlessly, without being stopped to allow the polarity to be switched). However, sometimes there is still a problem with electrical shorts. I'm aware that the insulated section is supposed to be longer than the train, but that's not the issue I've had. A few times when running the subway set into the crossover (especially at slow speeds), even though the polarity matched the polarity of the main track from which the train entered the crossover (which should've allowed the train to keep running seamlessly until it reached the other end of the crossover), the train would still stop and lose power shortly after the first car entered the crossover (specifically when the wheels on the trailing cars touched the insulated gap in the rails). I know the wheels can cause shorts if the train is longer than the insulated track, but that's definitely not supposed to happen when the train is entering the insulated track, and the polarity matches the main track. The subway set has 4 cars, all of which can fit within the insulated track, the other trainset is slightly longer than the insulated track but doesn't generally have the same issue because the cars are all electrically dead (aside from having metal wheels), whereas the non-powered subway cars have interior lighting and thus are not electrically dead.

jward

It sounds like the wheels on your subway cars are slightly wider than the insulated parts of the crossing (not crossover. That term has a completely different meaning in railroading.) The solution is relatively simple, one my grandfather showed me almost 50 years ago. Clear nail gloss acts as an insulator if you paint is on the metal rails that are accidentally contacting the subway car wheels. You don't have to paint much of the metal rail, just enough to stop the short. Maybe 1/8" at most. Eventually, the gloss will wear away and you'll have to reapply it. But it's a cheap, simple solution to your problem.
Jeffery S Ward Sr
Pittsburgh, PA

H5subway

Quote from: jward on November 16, 2020, 10:48:37 PM
crossing (not crossover. That term has a completely different meaning in railroading.)
Yes, I meant crossover (i.e. this: https://previews.agefotostock.com/previewimage/medibigoff/2df815873c13751c7f35a19dfad3040f/esy-032344888.jpg), which is what I have in my layout (the green section): https://cptdb.ca/uploads/monthly_2020_10/420403057_Newlayout.jpg.1352727b27bcd6d61829a2ba913a33f6.jpg

Quote from: jward on November 16, 2020, 10:48:37 PM
It sounds like the wheels on your subway cars are slightly wider than the insulated parts of the crossing
I wasn't referring to the plastic frogs at the crossing, but the insulated gap in the rails separating the mainline from the reversing loop (i.e. where the gray meets the green on the diagram). Sometimes (but not always) the train would lose power when going through that spot even though the polarity of the reversing loop was set correctly. Or, when the train is fully in the reversing loop and both switches (DPDT and controller) were flipped, it sometimes wouldn't start up again.

Another issue I've found previously when replacing plastic wheels with metal ones: the needle point bearings on the wheels sold separately were a bit too wide, such that when I first popped them into the truck frame they couldn't spin at all because they fit too tightly. So I had to trim both sides to get them to fit so that they could spin freely, but they still don't roll as well as the cars that came with metal wheels already intact (not to mention that the trim didn't quite turn out perfectly even). I wonder why the wheels that are sold separately aren't identical to the ones on those cars (that come with metal wheels), and if it is possible to purchase those higher-quality wheels separately.