Hi again!

Thank you for the input!
No, I promise! No oil in the switches for sure! The bottle just happend to be on the table when I took the photo.

Another thing. This thread will only apply for switches with item number 5202. Other switches has a different look and set up of moving parts and the tests and maintenance I present may, or may not work as intended on other items.
Let's continue...

What and how to check turnouts before you buy them
Check used turnouts carefully before you buy them. If they look good, straight and level and have the protective metal cover still under them, then they are most probably in good condition. I also use a simple test to verify the condition of the switch. I have a voltage controlled DC power supply set to 13VDC. At this voltage the switch should operate at first try, both ways. If that goes well, any problems that might occur later are recoverable. I would not recommend to buy it if does not operate at 13VDC and/or is bent and is missing the rear cover.

Small vs large semaphore
Avoid buying turnouts with the older type large semaphore. The modern passenger coaches are longer (more accurate 1:87) than those produced in the 50s and 60s (more like 1:100 scale). The new long coaches have a lot more of the detailing under them, which makes them lower and thereby hit the large semaphore on turn and derail.

Edited by user 20 February 2013 08:43:25(UTC)  | Reason: Removed the hint not to water wash. Washing is explained further down in the thread

Wow!

Ultrasonic cleaner? That was cool.
Seems to be kind of costy just to clean turnouts. I guess you have it for another purpose too, or?
It is probably the optimal cleaning solution, but maybe not available for very many "normal users".

Besides the way you use water with accelerated drying and in Ultrasonic cleaner, I still think it is a very good recommendation for most people not to use water as a cleaning liquid. Most of the turnouts I bought second hand over the last 10 years is not working due to previous water wash and corrosion resulting.

Edited by user 26 February 2013 13:21:19(UTC)  | Reason: Not specified

Common problems and the methods how to overcome them
The solenoid operates sluggish, lacking power and only sometimes makes the full travel
Solution: 1) Adjustment of the screws

The solenoid seems to work fine and goes “click-click”, but the turnout doesn’t switch position.
Solution: 1) Cleaning 2) Adjustment of the moving parts 3) Replace the spring

The turnout doesn’t respond at all when switched, or seems to short circuit the transformer
Solution: 1) Repair or replace cables

The lamp inside the semaphore is not lighted even though the turnout is powered
Solution: 1) Replace bulb 2) Repair or replace cables

Adjustment of screws
The motor that drives the turnout is really a 2-coil, 2-position solenoid. It moves a plunger made of a magnetic material, such as iron. The solenoid is fixed to the rail in both ends, whereas one of the ends is fixed by a screw. Untighten both screws, but only very little, like ½-1 revolution. Operate the turnout normally by grounding one of the blue cables. It should now work. Then tighten the screws again, but only very gently.




Cleaning
I’ve tested a lot of different methods of cleaning M-tracks and thought up til yesterday I found the easiest and most efficient way. For this I use two bottles of spray. One of them is “Electronic Cleaner” which contains mostly Isopropanol. The other one is simply pressurized air on a can “Aerosol”. Spray cleaner on the areas shown in the picture. Wait a 20 seconds and then blow dry with the Aerosol. Ready! However, François presented the Ultrasonic cleaning option and process. It's most likely both faster and much more efficient than my method. However, you need the machine first... If some dirt remains after cleaning described above, then use instead a soft toothbrush and Isopropanol. Clean the top holding the switch upside down and vice verse. If you have problems to find pure Isopropanol as a product in the shop, you can buy an additive for gasoline, which in Sweden is called K-sprit. It contains from more than 95% Isopropanol. The purpose with the additive is to prevent water condensation in the carburator and simplifies starting of the engine. Based on that you should be able to ask i a normal shop and get the right product.Use a can of high-pressure air to blow away any access Isopropanol after cleaning.



Here is how to replace the spring
The spring which connects the moving part of the solenoid with the rail is a sensitive device. The spring has in many cases been modified, shortened or pulled apart by someone who thought they thereby could solve an operating problem. Visit your local Märklin dealer and buy new springs. Make sure you get Märklin original spring.

Adjustment of movable parts
If you are unlucky, then someone in the passed has tried to improve the performance of the Märklin turnouts by bending the movable parts. It is of course against all logic that a new random looking shape of the metal parts in the turnout should be better than the original shape which Märklin engineered over the passed 50 years. Anyway. Look at the picture of how it should look and try to restore it the best you can.



Replacing the cables
The cables, yellow and blue, can break internally if someone has pulled them real hard. If you get no reaction from the turnout when powered, then try to power directly on to the solenoid. If it now operates, then the cables need to be replaced. Desolder the cables using a 25W soldering iron. Be very careful not to overheat the soldering points, while the plastic of the solenoid is very sensitive to heat. Connect new cables as the picture shows.

Hi again!

Okey, so above I have listed some common problems and methods how to overcome them.
However, the topic for this thread was not "Quick fixes for M-rail turnouts" but the more ambitious "How to make a total upgrade..", so lets continue.

(I suddenly realized the risk of writing a "know-how" article about turnouts people been struggling with for 50 years, but hey. I'm pretty fearless, so what?)

Why take it apart when it works fine?
So if my turnouts works at 13VDC, or even at 11VDC, with the K83 and all. Why bother doing more stuff and spending time on them? Well, it has to do with the statistics really. If you have one turnout which operates 99 times out of 100 and only have that turnout in your layout. It will practically take an eternity before you ever see a failure. However, if you have 100 turnouts which needs to be set for a certain route, the probability for failure is... significant. Your trains will not so often arrive to destination at all.

So the object with the coming actions is to reduce the risk of failure.
Let's start by disassembling the turnout.

1) Unscrew the screws and remove the spring, the semafor and the insulator paper.
2) Remove the lamp
3) De-solder the yellow cable from the lamp center contact. It is that cable that goes between the solenoid center pin and the lamp.
4) Straighten carefully out metal tongue "A" in the figure below.
5) Pull the metal parts out from the white plastic bobin.
6) See the picture below. "D" shows clearly dirt located on the chrome surfaces which adds to the friction. This is actually a turout which "passed" the 13VDC test.
7) Polish the surface with a piece of cloth. I use a polisher called "Autosol" on the cloth. Polish until the metal parts shine bright.
8) Assemble the solenoid again and test it.

Hi again!

Let's continue this serie about how to modify and improve the Märklin switch 5202.
This time we will adapt it to run wagons with DC-wheels.

Adapting for DC-coaches – ”The tape fix”
Märklin designed their wheels back in 1934 and then purely to be a toy product. The wheels were designed using a very wide and tall flange to prevent derailing and to accommodate use of the cheap style M-track, which rails really are bent plates, rather than solid extruded metal.
The large wheel flange of Märklin is not very prototypic and other manufacturers moved towards smaller flanges to get a more prototypic look.

Let’s take a look at what the difference in flange does to the dimensions of the wheel.



The M-track has wider tolerances compared to most rail systems in the market. It was designed with the wide flange and coaches and cars with DC-wheels does not run really well on the M-track. The much greater sensitivity to derail due to poor joints, poor cross section profile of the actual rail can be handled by tweaking the M-rail after the track work is in place. However, most wagons will anyway derail when the turnout 5202 is set to turn. Why? Simple! The support rail, which is to guide the wagons wheels into a turn is too narrow and doesn’t give the DC-wheels proper guiding. This is the support rail I mean:



This can easily be fixed by adding 2-4 layers of tape as shown in the picture.



I use a black tape intended for electrical installations. Why? It is black, which goes well with the track. It has a decent amount of thickness so I reduce the necessary numbers of layers to achieve proper thickness.

Verify the functionality by letting a loco push a wagon with DC-wheel set thru to turnout when set to turn.



The difference in price between the more detailed DC-coaches in 1:87 exact scale and the simpler more expensive Märklin wagons has given everyone a push to buy other brands than Märklin. Today, most of that difference, both in price and detail is mostly gone, so the reason to run DC-coaches on M-rail can really be questioned.

Wonderful topic, thank you for sharing!
I have been revising my M rail switches for a while now, with your guide.

I know this is an older topic, but I have found additional information to share here that might help people alot

I still had troublesome switches I couldn't get working properly on 12V.
My layout is fed bij 14,8Vdc, so 12V is the minimum I want them to operate perfectly.

After many hours of replacing parts, rebuilding the mechnics and electronics of the switches, I almost gave up.

Until I tried this:

Original method


New method


I reversed the iron block and rod!

The rod is kept in place by the coils (shift to the left for the photo's only). The rod is very loose and free, but still is held by the iron block.
Every problem switch I have, now works perfectly with this method, the sliding action has almost no friction anymore.
And because of the free movement of the rod, any inperfections of the switch of other parts, does not affect the operation anymore.

This worked incredibly good for me, maybe it can help others too.