Unpacked several Märklin locos and let them run on a test set up.
To my surprise, most locos couldn`t back up a train of only six free rolling two axle freight cars up a less than 1% inclination without
heavy wheel slip. Track wasn`t all too dirty, just a medium degree of
residue I guess, no pickup problems.

Among them a crocodile and an Ae6/6, both upgraded to 6090/37xx series standards.

The wheels of the non driven trucks were in an almost like new condition on some models, so no excessive wear, no oil dripping by overlubing the axle bearings and the sprockets.

The surfaces of the traction tires are gleaming in a shiny black and look smooth.

Some of the models haven`t been used for several years.

Could this be due to the decomposition of the tires or is this a result of the track condition?

I seem to remember that the locos had no traction problems on similarly dirty track earlier. Cleaning only one section of track brought back some of the traction power I was used to, but minutes later it was gone again.

Any observations?

TIA,
regards,
Manfred

Had no problem so far with aged traction tyres. I usually replace them when they get stretched and fall off the wheel. This may take many years of lok operation, I guess. My E 41 shows no slipping with a 5 coaches long passender train on a 5 % grades.

However, the traction tyres do not look shiny at all, mine get a very rough surface after few hours of running the lok. Perhaps yours have been in contact with some wax or thick grease.

I sometimes clean the tyres with Q-tips, usind gun oil and alcool (press the Q-tips against the running wheels). Got this advice here on the forum some time ago, and no problem with wheel slipping any more.

Hans Martin

When pricking into the tires with a needle I can move them, some more easily, some less. Some can be moved using my fingernail.

Okay, I`ll give it a try.
Hans Martin, what are Q-tips please?

Thanks to everybody for the suggestions.

Regards,
Manfred

I have had this, they can harden and even if left long enough and over exposed to oil become transparent and very hard, which when I refrubished an old class V200 bought at a jumble sale ment carefully cutting them off.

Also more ecent tyres seem less hardy, no bad thing as I feel they need changing from time to time.

John, Thanks!
Doctors advise not to use them for cleaning one`s ears.

Regards,
Manfred

After I bring locos out of storage, I always replace the tyres whether it is needed or not, they are cheap and usually easy to replace. Always have a few packs of each type here amongst my spares.

I would say just change the tyres.

I find that some of my locos "throw" tyres every now and then, especially when they have a bad crash or if the get "stuck".