Hello all! Today is Saturday. Doing chores at home. Running trains in between too! I consisted a 12 car freight train 6 of which are loaded with weight. The little 37652 V 362 (metal version) is at 1/3 throttle. It has no problem pulling all these cars at moderate speed. So strong for a switching loc? I Like the Tel-Ex couplers too!
I just switched it out with the 39120 E-10.3 and it is pulling just as smooth. I'm checking it for the pcb control problem I've heard about. Keeping my fingers crossed here! "I know, I know" it's a passenger loc.-- Not to worry, it's regular job will be to haul the Rheingold, and Helvetia train when the 39573 103 is resting.

It is normal that the lok gets warm. It shouldn't get hot though.

Märklin motors are strong. I have never seen a Märklin lok stall because the motor isn't strong enough. Typically you can hang on cars until either the lok slips, or, with the heavier loks, the couplers are pulled out of the NEM pockets. My tests (with somewhat heavier loks than the 37652) indicates that this happens when you have 70-90 cars or so. Much less if you have grades of course.

https://www.marklin-users.net/fo...ault.aspx?g=posts&t=4095

The pulling power of Marklin (and HAG) loks , with a few exceptions) is just fantastic and from an operational point of view, the main reason I have stuck with Marklin all these years.
As said elsewhere, I love running long prototypical trains, so pulling power has always been on the forefront of my "worries"
That means 10 to 14 coaches for D-zug or IC/ EC, 6 to 10 for lok powered TEEs, and 50-100 axles for freights.
My heaviest "regular" train so far is a 16 cars + sleeperette Rollende Landstrasse, fully loaded with trucks.
That is 136 axles!
On a 3% grade,a pair of Marklin Re4/4II in MU pulls this with *no* sweat, and so does an Ae 8/14 or a pair of Crocodiles(albeit non "prototypical" in these cases).
Same applies for a pair of any HAG locs!
An old Mä 3047, upgraded with a 5 pole motor and digitized, does it on its own.
A 3047 pulls a train 12 metal 346 series Schurzenwagen with lights effortlessly.
Same for an original MS 800 upgraded with tires on one driving axle.
A 3031 "Lil' Brute" with Telex, similarly upgraded, moves any of the above trains around the yard, or pushes 40 cars over the hump while shunting freight cars.
My old 3025 railcar, the champion of superfast running, shows no trace of any wear on its (helicoidal) gears...
Before building the layout, I also tested the limits of what a spiral track system can support: a 2.7% grade, using R2 K-track as minimum radius, allows to run all the above trains with enough clearance for overhead wire running and no traction problem for practically any loks with a metal body.
I clean the track daily with a SchienenBoy car, immediately after each operating session.
That's all it takes.
Some of my loks have been running for 50+ years, in similar conditions.
The old (pre 1965) ones are now mostly in display cases, but they all continue to pull trains regularly.
None has failed mechanically, as far as I can remember.
Last year I finally replaced the gears in my first lok, a 1951 RSM 800, just because I thought she deserved it after the million(scale)km she has covered for my enjoyement.
I just have a couple of electrical failures to mention essentially due to my own negligence (too much oil, ultimately causing a short in the armature)
In 30+ years I have owned some of them, HAG locos never gave any trouble, besides regular maintenance:lube, brushes, tires, pick up shoes, pantographs.
Not this much can be said of ROCO or Liliput: *none* of my (few) ROCO or Liliput loks still has its original moto
Bottom line: let'm' old Marklin loks pull and you enjoy!

Hey, Henrik!
I knew someone would pick this up!
Good opportunity to get some practical feedback
On the actual layout it will indeed be a dual C-track helix, with R3 and R4. But I wanted to test the limits of the system.
Low center of gravity cars (like the rollende landstrasse) or a 12x 24cm metal coach train had no trouble going up!
You think R3 for the "up" part would still be a liability?