Train stops/stutters after passing over turnout

Model Railroader Layouts and layout building
1

Hello,

I don’t have a permanent layout as of this post, so I’m running Atlas True Track on the carpet. The carpet is pretty beat-down, so it’s very low-pile and offers a reasonably flat surface. The “layout” consists of an oval with a passing siding. 18" radius turns, two manual turnouts, and two9" straights. In testing, this occurs in both DC and DCC (Sprog 3).

When a locomotive (or locomotives, it doesn’t matter if I’m using a consist or not) passes over the turnout and onto the curved section of the track, as soon as the rear truck passes onto the curved section, the locomotive will stutter or sometimes even stop. If I increase speed before entering the turnout, sometimes this helps, but not always.

This only seems to occur if the locomotive is headed in the direction that would allow it to go to either way on the turnout, not when it’s coming across the turnout in a manner that it’d have to pass the turnout and back up to use the diverging track (does that make sense?).

I’ve swapped the turn out, and this still occurs. I also added two turnouts to the other end of the oval (effectively increasing the length of straight track between each curved end), and this occurs on the side using the new turnouts as well. Again, just entering and once it gets to the curved track immediately after, not in the opposite direction.

Any ideas?

Thanks,

Tim

2

Trying to run on any type of carpeting is not a good idea, and it would be better if you can select a different location.

Possibly loose rail joiners on the Atlas track where the turnout connects to the loop. Make sure the track is snapped together properly.

Adding an additional set of power feeder wires to the track beyond the turnout may also help.

3

Could be a lotta things. The turnouts likely have non conducting plastic frogs. The locomotive[s] may not be picking up juice on all wheels, so when the juice collecting wheel goes over the plastic frog power is lost. Could be something on the bottom of the locomotive is hanging too low and is riding up on the cross rails and lifting the wheels just far enough off the track to break contact. Could be loose rail joiners breaking contact as the weight of the train pushes the track up and down. Could be the movable rails in the turnout (the points) aren’t getting power all the time. Could be coupler glad hands are low and striking the turnout crossrails.

I’d trouble shoot by simplifying things. Try it with a just a single locomotive. Try it with the locomotive facing in both directions. If you run real slow can you get the locomotive to actually come to a full stop and stay stopped? If so, is the locomotive still getting juice? (headlamp stays lit). Is is electrical or mechanical ? (locomotive is catching on something). Get a 12 volt test lamp (or a multimeter if you have one) and check that all parts of the turnout have power. Put the locomotive upside down on the table and check that all wheels are picking up juice, touch leads from the power pack to each pair of wheels and make sure the locomotive runs.

Good luck.

4

It’s time for a real layout. You will never have reliable trackwork on carpet.

If nothing else, go to an appliance store and ask for one of the big cardboard boxes refrigerators come in. Use that for your layout base. It’s flatter and more solid than carpet, and you’ll reduce the amount of rug fuzz you get inside your locomotives.

5

Dstarr,

Actually, all of those things sound plausible (aside from maybe the electrical pickup of the locomotives, because it affects locos from Trainline all the way through Athearn, P2k, and BLI. They’re all new-ish, relatively speaking (see next comment), and I keep my equipment clean.

MisterBeasley,

While I agree whole heartedly, I don’t have the freedom to setup a layout currently, so it’s just temporary for now. I am going to try to get something stiff to lay the track down on at the very least.

Thank you both for the suggestions on where to chase my gremlins. It’s much appreciated.

Tim

6

It might be that the turnouts are flexing a little under the weight of the engine, just enough to interrupt the electrical current which, as other posters have said, is already challenged at the frogs and beyond. Sometimes adding weight to the engine on a temporary basis (a small sandbag for example) is a way to test if the engine is flexing too much over rough track to maintain contact).

It sounds like you are running your trains where you have to run them, so the advice to “get a real layout” is likely not helpful. Huge sheets of cardboard from the appliance store are also unlikely. But the idea of stiffer support under the track than even industrial grade carpet provides has merit. I would suggest perhaps thin sheets of shirt cardboard or an opened manila folder under the turnouts to give it just that much more stability when the engine passes over might at least tell you if my theory holds water.

What would be interesting to see is if a small wheelbase steam engine with no tender, so an 0-4-0T or 0-6-0T, would stall at the frog. That is a common problem.

Needless to say sometimes circumstances mean that you are relying on the tiny amount of contact from perhaps just one wheel to actually pick up power at some point, so the wheels need to be perfectly clean.

Dave Nelson

7

Dave, Thank you for your reply. While I don’t have a shifter to try out, manilla folders are an easy option. I’ll try to give it a go this weekend and report back. Tim

8

Your running about a 4ft x 5-6ft oval from the sounds of the track. You could try those “handi-panels” found at HD, Loew’s etc. If storing a 4x4 is a problem, use 3) 2’x4’ laying them to form a 4’x6’ base. 1/4" luan, MDF or birch should give you reasomable support on the carpet.

If you are constantly setting this up and breaking it apart, the rail connectors of that Atlas track could be causing loss also, It’s a good idea to add additional feeders to a few spots to compensate

9

Well, it’s definitely the turnouts. I checked my rail joiners, tightened a few, and placed stiff paperboard under the turnouts and their surrounding track. Same result. I swapped one of my original turnouts out for a spare, same deal. I have one last pair of terminal rail joiners that I’ll try adding into the track right between the turnout and the first section of curved track leading off of it.

Thanks for the help so far.

Tim

10

We’ve been helpful? lol

If even just temporarily, mount some track and the turnouts on a truly solid and flat surface. Perhaps even use masking tape to really fasten down the edges of the track. If you still have the same problem then we might have to conclude that the particular locomotives you own just catches the turnout’s dead spots at the worst possible place. That can happen

Adding more electrical connections can only help I suppose.

Dave Nelson

11

Lol yes, you’ve given me things to try. The suggestion about the locomotives hitting the dead spots at the perfectly wrong times doesn’t seem quite right; GP9s, SD9s, GP15s, GP30s, GP38s, an F40PH, and 8-40BWs all exhibit the same issue. I could attempt to set up on a table, however the issue becomes WiFi connectivity; if have to move my laptop out there as I use a Sprog 3, and the WiFi connectivity is spotty in the dining room. So for future reference (aka, when I get to build a permanent layout), are there turnouts specifically designed for DCC? Thanks, Tim

12

A couple of details that may shed light on the issue: 1. The issue only occurs when entering the turnout in a way that would be divergent, like when you’re on a highway and pass an OFF ramp. It does not occur in the convergent direction, like when you pass a highway ON ramp. I don’t know how else to describe it outside of that example. 2. Taking the turn out (like taking the off ramp in #1) does not cause the locomotive(s) to stutter. 3. It occurs more often when the second truck of the second locomotive crosses onto the plastic section of the turnout. Sometimes on the second truck on the first locomotive. 4. All track power momentarily blips; I had a pair of Geeps in a consist parked on my siding with their lights on. When the SD9s would stutter, the Geeps’ lights also went out.

13

Turn out the lights and watch the frog area where the rails form a V.

Any sparks present?

14

While I am not able to test for sparks tonight, when I was looking to see when the stuttering would occur on the track, I did not see any sparks. I also didn’t see or feel any scorch marks that might indicate an electrical arc on the track nor any on the SD9s’ wheels. So I feel 95% confident that there weren’t any. The room wasn’t pitch black, but it wasn’t terribly bright, either. (It was a gloom day in Pittsburgh today.)

Thanks,

Tim

15

AS a retired 12"–1’ RRer as well as HO modeler, a little help on the vocabulary: When you come into the turnout (switch) from the single line end, that is a "facing point " move; when approaching from either of the tracks on the other side of the turnout, that is a “trailing point” move. Not trying to cut you down, we all have to learn somewhere along life’s journey. I know this won’t solve your problem, but I always like to pickup the language. Hope you do, too, and enjoy the hobby as almost all do. Best wishes for Happy Modeling. JWH

16

I appreciate that. I knew there were actual terms, but I’m glad that I was able to explain it in a way that at least made sense. Thanks. Tim

17

Tim, after re-thinking your problem, I have another take on it. Since you said you are running your trains on carpet (which others have addressed, and I agree is not a good idea), I would check where the switch-point rails contact the stock rail (the moving part of the turnout contacting the non-moving part. This is probably a power routing turnout, which means that it gets it current through that small contact point. If power there is intermittent, once you pass the turnout, there may not by any current in the siding. One way to check: when the train stalls, press the turnout rail against the stock rail. If the locomotive starts again, you’ve found your culprit. With a small wire brush, clean the sides of the rails; the stock rail and the back side of the switch-point rails.

18

Now that sounds entirely possible. I’ll try to test ASAP. Thanks! Tim

19

Marlon, great point- now I’m not scratching my head as much. Could be a considerable amount of dust, dirt or carpet fiber there.

20

So, I was able to do some further testing, and I think I may be even more puzzled than before.

I cleaned the wheels on a known good loco (Athearn GP40X, TCS T1) by running it on a paper towel soaked in rubbing alcohol. I then also cleaned the turnouts stem to stern in the same manner, and did clean some black stuff from the contact points. So far, so good.

I build a consist of the known good and a brand new (to me) locomotive, another GP40X with another T1. The new loco can circle the track fine, the cleaned one stops after it crosses the plastic part of the turnout, as well as a few other sections of brand new, just opened from the package, track.

So then I go back to my BLI SD9s. Clean their wheels. Same result, when the rear truck of the lead loco hits the plastic, it stutters. When the rearmost truck of the trailing locomotive hits the plastic, stutters.

I swapped out that turnout for a brand new, just removed from package turnout. Same result.

Notice that in the examples, the GP40X would stop, whereas the SD9s would stutter.

Out of curiosity, I physically turned the locomotives around. They ran flawless in the opposite direction.

I drew a diagram (below) to better illustrate my point. The problem turnout/location is circled in red. The direction that I have trouble running in is indicated by the red arrow, while running fine is indicated in green. The blue hashmark indicates where the terminal connectors are.

And for your trouble, here’s a couple videos illustrating that my SD9s actually do run in the “green” direction:

http://www.youtube.com/watch?v=YigrkHNQ3Yk

http://www.youtube.com/watch?v=Owbq4pOIORg