Hi

[bmassaer]

I have two old 4.5V train sets, both with engine and battery car, both not working. Changing the battery does not help me out. How can I know which part of the train is not working and needs replacement?

I do have a (borrowed) multimeter bot don't really know if U use it the right way...

 

Bart

[deraven]

My top bet would be corrosion of the contacts somewhere in the battery car.  Use the multimeter and see if you get 4.5v from the contacts on the side of the car where you plug in the power cable.  If not, you need to dig into the car and see if there's a broken bit, corrosion, etc.. If that's good, plug in a power cable and test the other end of it to make sure there's not problem there (replace the cable if so, obviously).  Once you have power to the end of a 4.5v cable, if the engines still don't work that's where the problem lies.  You could also take the battery box out of the picture by just wiring up a few batteries directly to a 4.5v cable, make sure you've got good voltage to the connector end, and then plug that directly into the engines and see what happens.  It's possible that everything is dead/broken, but hopefully some parts in that mix are workable and you can easily fix or replace the rest.  

[rsb0204]

Aside from what deraven said, I've noticed these old motors can get "stiff" over time. When I got my 113 it hadent been ran in decades, and didn't move at all when I first turned it on.

After much fiddling I went outside for a smoke break, and forgot to turn the battery box off. About 10 minutes later I came back in and the train wasn't where I left it, it had managed to move about 2 inches. I imagine the the grease/oil had managed to "set" over the years. 

after that I left it on and kept a close eye on it, and indeed it was moving, just almost inperceiveably slowly. As I continued to let it run it started to move faster and, after about half an hour or so it seemed to be functioning normally.

Now, i doubt this is the cause of your problems, but I feel it is a possibility worth mentioning.

[freestorm]

Can you tell us which 4.5 Battery box do you have?
You can check on brickset: https://brickset.com/sets/theme-Trains

First, I will check the continuity of the cables with your multimeter
I you don't know how to do it, this page can help:
https://www.ifixit.com/Guide/How+To+Use+A+Multimeter/25632#s64987 

Sometime current batteries are not the same as they was in 80'
I mean the size of the polarity plugs, not the size of the battery itself

 

 

 

[bmassaer]

I have both de 161 battery wagon and the black battery box from the 118 train set. Today I opened one motor and found out that the motor was running when connected directly to the batteries. The wheels were not turning because lot of dust blocking them. So after cleaning, the first motor runs!
The black battery box was not functioning because indeed the polarity plugs of the batteries did not make contact - some silver paper between the battery and the contact helped. And then also the wire makes a bad connection... But after a day of cleaning en unscrewing, I managed to get one train running!

Now I am ready to work on the next one ;-)

 

Bart