Hello John
here a user of a CS3 and Rocrail and having used M track for decades.
M track is excellent but being made of iron ("soft steel") it is prone to corrosion.
While applying WD 40 is excellent for rust prevention, it may cause the dust to stick to rails and wheels
A contact liquid helps certainly BUT ALL must be cleaned: the track, the wheels, the wheel bearing, etc.
Never use an abrasive (sandpaper) except the "erasers" (Roco, or equivalant). I personally use grit range 5000 to finish painting on cars.
It leaves no grooves on the metal to later retain dust.

Contact tracks 510(, 5106. They were the first version on these contacts with the contact zone frequently being in slight recess compared with the normal track.

For Rocrail, the best is to have long contact stretches (occupation zones (1 to 3 m long which is impossible with M track unless serious changes on the track.

Some M track users detect trains using the current detection (M88 DC 60882). It works well but cannot detect a car / wagon without a slider and a lamp / resistor so they manage to add a lighted coach at the end of each consist or a lighted "Begleitungswagen" train conductor wagon) that way the safety is optimal.

Here is my present Rocrail layout using C Track
(sorry not M Track anymore)


The best way to avoid contact issues is to use the train regularly (once a week)

Cheers
Jean

For some reason there seems to be a requirement with contact tracks to have the same current flow so with the M tracks just try reversing the connections. I never understood why but I believe I had a similar issue with C-track.

Ahh, thanks for the clarification Jean. It is so long since I have dealt with M track contact sections that I can't remember the catalogue numbers.

THe 5146 / 5147 / 5213 are very finicky and not very reliable after they have been installed and used for a while.
I replaced all of mine with the 5104 and 5105 contact rails.
They work like a charm, you just need lo leave enough space so that a train will not stop on them.
The 5146 only get activated by a slider, the 5104-5105 get a jolt every time that a set of wheels goes over it, so with a long train that gives you at least 25 attempts to get contact.
Just my dollar's worth (because inflation is playing havoc here over the last 5 years).
Tim

Thanks Jean. Just to be clear, I'm not cleaning with standard WD40 but rather a different WD40 product (WD-40 Specialist® Contact Cleaner) specifically designed for cleaning electrical components, and it seems to work very well. After working with my two trouble areas a bit more this morning, I finally switched the two contact track pieces with others on my layout that I believe were "new old stock" from my eBay purchase and this seemed to solve my issues completely. Thus, I can only conclude that the two contact tracks in question must have some other issue. I'll be doing a bit more design work on my expansion and perhaps I'll incorporate a couple of "enter2in" sensors to eliminate the need for a 2nd physical sensor for a couple of blocks. If that doesn't work I might investigate using some Azatrax infrared sensors as I've been curious about trying those as well. I appreciate all your help!

John