Locos run very slowly over 90% of the layout.

One of my two circular tracks has started to run very slowly for 90% of the circuit but is fine for a small section between points. Any suggestions what could be causing this please. 

   Kettrin Imp and welcome.

You don't say whether your running a DC or DCC layout, but I suspect the problem has something to do with where your power feeds are and how clean the track is.

It also may depend on what track your using and how it's connected. Rail joiners are not great at conducting power.


Ed

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Hi Ed,
Thank you for your reply. It is a DC layout using Peco SL-100 track with rail joiners. It was fine a few days ago but all I have done is lay some ballast at two sets of points and let the PVA dry. The track is clean and the power drop off is not near the points I’ve just ballasted.

Steve.

There's your cause Steve - if all was fine before laying the ballast, then it must be to do with the ballast ………………….

Is it completely dry - no possibility of dampness shorting on switch rails or check rails ?  Which ballast did you use ?  Any chance it could conduct a tiny current to ground thus reducing the current available at the rails ?

Check all these then if necessary, add an extra power feed between the two points.

Kettrin Imp said

Hi Ed,
Thank you for your reply. It is a DC layout using Peco SL-100 track with rail joiners. It was fine a few days ago but all I have done is lay some ballast at two sets of points and let the PVA dry. The track is clean and the power drop off is not near the points I’ve just ballasted.

Steve.

From “Post #291,559”, 23rd February 2025, 1:57 pm

At each set of points, try sliding the rail joiners BACK away from the points to break the electrical contact ( you may need to do some fiddling with a craft knife to pair off some rail chairs, to allow the joiners to slide back. Then try each section of track before, and after the points to see if the sections are good or still running slow. It sounds like you have something causing resistance and drawing down power, so isolating the points you have ballasted will first let you check the problem IS with the points and not some random Gremlin creaping in while you were working on the track. If the track is ok you can then re connect each of the fish plates ( slide them back into place) and keep trying the track until the short re occurs, which should help locate the problem

HTH

Matt

Kettrin Imp said

the power drop off is not near the points I’ve just ballasted.

From “Post #291,559”, 23rd February 2025, 1:57 pm

Very odd, but I've had problems in the past after ballasting.

Some more information as Petermac has suggested might help to solve the mystery and you could also try Matt's advice, which might solve the problem.

A picture of the layout with the ballasted points and an indication of where the power is supplied to the track, could also be useful.


Ed
 

Petermac said

There's your cause Steve - if all was fine before laying the ballast, then it must be to do with the ballast ………………….

Is it completely dry - no possibility of dampness shorting on switch rails or check rails ?  Which ballast did you use ?  Any chance it could conduct a tiny current to ground thus reducing the current available at the rails ?

Check all these then if necessary, add an extra power feed between the two points.

From “Post #291,561”, 23rd February 2025, 2:19 pm

Thanks for your reply Petermac, I applied the PVA last Monday using Woodland Scenics grey blend. I would have thought it should be ok by now, maybe I could use a hair drier on the affected points.
Thank you to everyone for the suggestions, I will give it a go tomorrow.

If you have a multimeter go around the track to a) make sure you have continuity (resistance, ohms), and b) track voltage (volts) is what it should be. if you are using unmodified Peco electrofrog points they are probably power-routed. If you are not familiar with this it means that power through the points and often beyond is carried through the switch rail. As mentioned if glue has got between the blade and the rail it's effectively insulated. Use some fine emery paper to clean the blade and the rail. If that doesn't work lift the points, soak in hot water to dissolve the PVA. Did you "wet" the PVA with alcohol? If yes it will creep into the smallest of gaps.

What are you using for rail electrical connections? Rail joiners? Same issue here, if PVA gets into the connection it's insulated. Do you have insulating joiners after the points?

If one of the connecting wires under the points has become detached you will have a dead rail.

The multimeter will identify what sections are dead. If you don't have one they are not expensive. They should be around £10 in the UK.

Odds are you have glue in the switch blade/running rail contact. The other area is the disc where the closure rail meets the stock rail. Even if it's fixed with glue the points will still work but not conduct. Best to protect with masking tape in the future.

Nigel

I note that the tracks are circular.  Are there insulation gaps in the rails anywhere?

Terry

Well I have sorted it out, not sure quite how. It was still running very slowly this morning so I tried isolating the recently ballasted area but it didn’t work. On returning the points to normal the loco started running normally again. I think it must have been something to do with the set of points on the other end of the layout. Very strange.

Thank you so much to everyone who took the time to reply. Take care.
Steve.

The problem: you have a perfectly working layout which you then ballast and you apply some form of adhesive to the ballast.

The symptoms: loss, or partial loss, of power seemingly at random over smaller or larger areas (affects DC and DCC)

The diagnosis: adhesive is non-conductive and has found its way into the rail-joins and / or is lining the internal faces of the rails which are just as critical for power supply as the tops

The treatment: clean tops and inner faces of the rails. Only where wheel-rims touch - you don’t need to wipe off any weathering on the “web” which is the narrower upright section of the rails we sometimes paint with rust. If that doesn’t fix it go around with a multimeter to identify which sections of track are affected; if possible wiggle the joiners slightly to-and-fro to dislodge any ballast adhesive. Consider adding more power droppers if you have a bus-wire and really stubborn sections. You can also get an improvement by carefully applying RailZip2 to the affected joiners. One pin-head drop is plenty.