Some of our customers operating with Märklin C track have reported derailments. When rechecking the gauge of the wheel sets we have noted some deviations that were just outside the permitted tolerance.
Should you experience a somewhat jerky running behaviour of your class 151 when traversing C track turnouts, you can remedy this easily and quickly. All you need is perhaps 15 to 20 minutes and some tools, which one would normally find in any model train enthusiast’s workshop.
The following steps are only necessary for locomotives with the part numbers 31030 (green) as well as 31032 (traffic red) of the first production batch. For all models delivered as from mid 2012 the wheel gauge has been checked several times in the factory. Locomotives with the part numbers 31031, 31033 as well as 31034 should run trouble free and should not require any corrective measures.
Please read these instructions carefully before starting the modification. Although no special skills are necessary, you will need a little bit of patience for a successful outcome.
If you do not want to do this yourself, we recommend contacting your hobby shop.
We apologize to all persons concerned regarding this issue and hope to meet your expectations in terms of quick and non-bureaucratic help.
For changing the gauge of the wheel sets to 14.0mm you will only need a few tools:
- A small Phillips screw driver
- A sliding calliper, which facilitates locking a set dimension
- A clean and well lit work place
- Ideally a foam repair cradle
We start with bogie number 1, which holds the centre pick-up.
Turn the locomotive on its back. Take off the centre pick-up by holding the pick-up at left and right with the tool provided. Then push the legs of the tool together and pull off the pick-up towards the top. The pick-up is held by two clips that are released easily after a somewhat powerful jerk.
After that you must remove the gear box cover. First remove the three Phillips screws, and then lift off the plastic lid. Attention: The sensor stirrups at the outer axle run through two slots in the lid. They should not be bent or removed from their position! They must stay in place!
Remove the rear axle and the centre axle with the aid of the tweezers. The axles are only laid into the gear box and can easily be removed. Please make sure that the contact strips (for current pick up) are not inadvertently bent!
Now set a distance of 14.0mm on your calliper (13.9mm to 14.1mm are also OK) and lock this dimension. The calliper must keep this dimension even when you try to squeeze the pliers! Most good callipers have a knurled-head screw for this purpose.
Now we come to the most critical part: first put the calliper between the wheels and then press both wheels together (from the outside) with your thumb and index finger.
Don’t be shy! If you push hard enough, the wheels will move closer together with a slight snap. The calliper assures that you will not push the wheels more than necessary.
Repeat this process with the middle and rear axle.
Never use a hammer or similar rough aids! There is a possibility that one wheel may cant and result in a wobbly axle.
Unfortunately we cannot remove the front axle: the sensor stirrups are in the way. In order to remove the sensor stirrups you would have to remove the bogie. This, in turn, is only possible if you cut all cables leading to the chassis. Since there are many wires in the class 151 this means some extensive operation and may also cause some damage.
So, let’s not do this and rather proceed as follows: Lift the front axle from its bearing as far as possible (the sensor stirrup acts as a restraint). The axle should be clearly visible above the bogie sides.
Put the calliper between the wheels in the same way as you did for the middle and the rear axle and then press both wheels together (from the outside) with your thumb and index finger. This requires some force since one cannot grip the wheels properly.
Please make sure that you do not damage any of the fine details of the bogie side frame cover and do not cant the wheel set!
Now we "only" have to reinsert the axles. We begin the with the outer axle. Press the contact tabs together with the tweezers and push the axle back into its bearing. It is very important to keep the contact tabs straight; they must touch the inside of the wheels properly and may not be bent!
Then follows the middle axle. Reinserting this, is somewhat fiddly, because there are four wheel wipers (two on each side) that must be pushed together, before one can reinsert the wheels. It works best if you use two sets of tweezers. Take your time. Bent wheel wipers can hardly be straightened out.
In comparison it is child’s play to reinsert the inner axle again.
Put the gear box cover back in its place. Please make sure that the two sensor stirrups sit straight and move freely through the two slots in the gear box cover. When you push the stirrups, they must first move inwards and then spring back into their original position once you have released them.
Finally we fix the gear box cover with the three screws and remount the centre pick-up.
Then deal with the second bogie in the same manner.
After having read these instructions, some customers asked if the wheels would not wobble after this procedure. We would like to comment that we have re-gauged numerous locomotives in-house, and have not experienced any running problems.
Other customers raised some concerns if it would be possible to achieve the necessary precision with the aid of the calliper and manual adjustment. We can also reassure you regarding this point: The spacing between the inside of the wheels of 13.9mm and 14.1mm is perfectly suitable for Märklin tracks.