Slow spots

Poor connection somewhere. Check grounds, and maybe a bad track or pins in track not connected probably.

Rick,

If you don't check the voltages correctly you'll be fooled into thinking that there is no problem, when there actually might be one.

Track voltage, from center rail to outside rail, should read exactly the same as the voltage across the posts on the transformer connected to it, as long as there is nothing on the track -- no engines, no lighted cars, no operating cars, etc.  This is the 'no load' voltage and will be the same no matter where it's measured on the layout.

Once you place something on the track that draws current, like the rolling stock mentioned above, track voltage will drop.  Slightly, if you have nice tight connections between track sections, enough extra power drops around the layout to compensate for the length of the track, and rolling stock that draws low current such as a lighted caboose.  More, maybe much more, if the track is dirty or doesn't connect together well, if there aren't sufficient extra power drops, or the item on the track draws larger current, such as a full string of incandescent-lighted passenger cars, or a large postwar locomotive.

It will drop less near the transformer.  It will drop more at the far end of the layout because of distance, especially if there aren't enough drops, or wire has been used for the drops that is too skinny.

You should check the voltage from center to outside rail at your slow spots, with the train or cars on the track and operating on top of those spots.  Instead of reading 'no-load' voltage you'll now be reading 'at-load' voltage.

This is the best way to get an accurate reading of how bad the slow spots are.

Let us know how it turns out.

Mike

That's a garage full. You need lumber....saves the knees.

Anyway, it seems that your train is slowing on the curves, which has to do with friction from the train wheels and flanges on the track itself, rather than the current available (both, probably). Add poor-rolling PW trucks and a Pullmor with poor high-speed gearing in the loco (1 or 2 motors?) and you can have a friction problem. The broader your curves (you've got the room, maybe) on your mainline will eliminate quite a bit of this.

Real RR's deal with this sort of thing. "A curve is the same as a grade." Some real locos have even been equipped with "flange oilers", that lay down a small amount of lube on the inside of the rails so the train behind will roll around certain curves more easily, economically, and at a higher speed.

I echo what Mike said above. Dirty track pins are often the culprit with tubular track. If so, clean the pins and the track if you can. I use contact cleaner spray for the track tubes.

What size wire did you run for your drops?
How often did you install one?
Did you use lock-ons or solder the wire to the rails?
Do other loco's show the same symptoms?

It looks to me like the slow spots are on the curves. I'd start there.

Bob

From that video, I have to agree it's the curves and not necessarily any power issues.  There's where cruise control comes in.

It's the curves.

Rick, First of all, nice job on the layout! Watching the video, I tend to agree with, the wheel flange friction on the curves theory. You’d notice a similar slow down in speed, where you currently have no problem, on the straight run, if you created a slight incline.

As mentioned above, with a nice traditional style layout and equipment likes yours, I believe that’s fairly typical behavior. Don’t make yourself crazy trying to find a voltage loss anomaly. It’s possible you could find one, but I doubt that’s the issue.

As Gunrunnerjohn, mentioned, that’s where cruise control comes in.

I honestly think that engine is running on your layout pretty good. If you haven’t already tested your other engines, you should, and just sit back & enjoy!

I agree with Gunrunner.

I have a figure-8 inside my layout.  One of the curves is all O-31 sections.

Most of my shorter engines glide around it with no slowdown.

But, I have a big "larger than scale" 44 ton switcher, with two motors and two four-wheel trucks spaced pretty far apart, and it always slows down going around this curve, by at least 1/2 of its speed, and if I run it at a slow speed that keeps it moving on the rest of the layout, it will just stall out on that curve.

It is not command control, so using conventional throttle, I have to nurse it around this curve.

Also, is it possible that the track sections where the slow -downs occur are brand new track?  If so, Gunrunner taught me that you have to triple clean it with a caustic cleaner, like mineral spirits or 96% isopropanol, using a greenie scrub,  because it is coated with "something unknown."   This significantly increased the speed on my new track sections.

Finally, if you are using used track, curved sections, you will often see that the ends of the rails are bent or twisted a bit, because of people pulling the track section "straight up" while the track pins were still connecting it to the next section.  So really inspect these sections, because often, you have to gently bend the tops of the rails gently inward or outward, using a real track crimping tool, to be sure that the wheels stay in close contact with the rails when traveling over these curves.   Sometimes, I run a short section of wire, from one outer rail to the other, just to make sure that there is good neutral contact to the wheels when the train runs over the piece.

Mannyrock

Thanks to all for your responses. Great feedback!

You need “MORE” Track Feeds. AND Cleaner Track !!………. AMEN

FREDSTRAINS

Power drops especially on a layout your size should be every 3 feet AND ON EACH LEG of a switch.

@prrhorseshoecurve posted:

Power drops ... should be every 3 feet ...

Every 5-6 track joints is more than adequate. That makes each section 2-3 joints away from a power feed.

Check your track with a bubble level.  Preferably one that's 8"-12", i.e., no longer than the locomotive itself.  Lay it along the track, as the train would run.  I would be willing to bet that the one curve by the transformer lies at the top of a grade.

If you don't have a level, just try running the train in the opposite direction around the loop.  If it flies into the transformer curve when running in the clockwise direction then you need to level your table, or the track itself.

A dual-motored "growler" like a postwar Lionel 2343, or a newer, can-motored loco with a lower (numerically higher) gear ratio--like an MTH 0-4-0 "Docksider"-- would probably creep around the layout without slowing as much or stalling.  Single-motored diesels and most Postwar steam are going to find the voltage drops and low spots every time!