I have stopped using Märklin double slip switches because freightcars with two axle trucks don't always want to go straight thru them. Longer cars seem to have more problems than shorter. So I have replaced one switch with a Märklin crossing. But since they share the same metal chunk in the middle of course the cars have the same problem. Before I arm my self with my Dremmel tool and start guessing have you seen the same problem and come up with some cure? If the trucks swing when going thru maybe they catch the points (green arrow) and go in that direction instead. I though about removing the parts in the center, black arrows, thinking they wouldn't be there if I would build my own crossing. But because the cars don't derail, they turn and then derail the whole train, I'm not sure they are involved. Also I have never had the problem with Märklin cars, if I run any, only with AZL and MTL, wheel dimensions? Rokuhan crossing seem to have the same basic design. MTL doesn't have a crossing.
Thanks for the answer. I have problems with too many cars so I still blame the crossing. But I though of try to switch to Full Throttle metal wheels and test. Is there a gauge tool for checking the wheels? If the wheels are too far apart or too close I guess they can't be adjusted. That would break them. Also part of the equation is that Märklin switches and crossings are made for Märklin wheels. And Märklin wheels usually have monster flanges.
Check your couplers to be sure they are centered in the pocket. I had a MTL car with truck mounted couplers where the coupler was not centered. The car kept derailing the lead wheel set to the right. after rotating it 180* the trailing wheel set would derail to the left. It was just enough pressure from the coupler to push the wheel set to the side and cause it to ride up over the rail on the double slip switch David
Correct. The problem is the wheel itself. The Marklin crossing and switches are not designed on the traditional way. To improve better electric contacts, they installed ramps and grooves, where the wheels are running on their flanges, so other than Marklin wheels, the flanges are not guided thru as they should. If you look closely, there are no traditional frogs with corresponding guard rails. The best solution is to get Rokuhan crossings.
...in my opinion it is best to avoid these crossings, unless you are able to build your own (e.g. from fast tracks). I have converted all my Märklin roling stock to mtl couplers and have also isues with short wheelbase Märklin cars at Märklin crossings.
I remember, long time ago, our great friend the late Bill Kronenberger mentioned, the first versions of Marklin crossings worked OK with MTL cars and locomotives, and he constantly searched for those. Sometimes in the 80's Marklin modified the crossings for worse.
Thanks for all suggestions. My yard I try to change the design so I don't have any crossings but on my double loop diorama the crossing is the centerpiece. The Rokuhan and Märklin 13 degree crossing looks basically the same to me. The 90 degree Rokuhan is closer to what I wanted but I don't have the space. I did look for a FastTrack template/kits for a crossing but I could only find switches in Z-scale. I wanted something like 30 or 45 degree but there isn't enough space for that either. I have one blue Rock Island 40' boxcar that refuses to go straight, it turns right. That is a good candidate for testing the other ideas you came up with. Also I have a new MTL BN F7A that runs perfectly alone or in front of a F7B-unit. But behind a BN GP35 it turns left going thru the crossing every time. I wonder what the big change was between the old and the new version of the Märklin crossing. I'm sure I have a new one.
The problem is the distance between the two axles of a truck, and whether there is any side pressure from a coupler, Cars with body mounted couplers seem to work better than those with couplers mounted on the truck. Longer trucks like 3 axle, and two axle passenger cars go through easier because the distance between outer axles does not allow the truck to move far enough out of line to go through the crossing and take the diverging route. Marklin version of bettendorf truck have a longer wheel base and they also to not pick this crossing because of that. The crossing is a 13 degree crossing, the same angle as their 110 mm long turnouts and that is a standard turnout angle so standard bettendorf truck can easily turn and make that angle so i takes off in the other direction, in the case of mismatched engines like GP 35 and F7 one engine is either pushing the other or pulling the other so there is pressure on the coupling pulling or pushing the first truck of the pulling engine or the lead truck of the pushing engine into the diverging route. Metal wheel do help some because the flange is better shaped and not a cookie cutter. on the good version of the Marklin crossing the version that worked had a height difference between left and right track in the crossing which helped keep the cars on the right line through the crossing, later versions did not have this difference and the performance was degraded. in the process the flange height on most wheels was decreased and that has lead to the enhancement of the problem. I have been suing Rokuhan versions recently and they seem to be allot, but mismatched pulling power can still pick them, but over all performance seem to pretty well eliminate this problem in the Rokuhan version. They will have a double slip version of the crossing available shortly and that should make it even better. In the double slip the point rails act as guard rails making sure the car can only go the one direction In the thirteen degree crossing the need to get continuous power through the crossing has lead to a design that has no room for a guard rail. This is not he case with 45, 60, and 90 degree crossings . The 13 degree crossing is sure to derail standard box cars if they have truck mounted couplers and you are pushing a string through the crossing or if you have a long trains and the crossing is at the bottom of a steep grade, and the other is long string of cars with heavy drag coming trough the crossing out of a sharp, or into a sharp curve.
Thanks for all the great input. I think you are perfectly right Garth, a shorter truck can go more sideways that a longer one. Also as you and David wrote, if the coupler isn't centered then you will pull/push the truck sideways through the crossing. I noticed that with the blue Rock Island boxcar. No problems what so ever rolling the car by hand by it self back and forth through the crossing. But couple it onto another car and the couplers doesn't meet and I have to line them up manually. And then when I run the train the blue box car turns and derail the whole train. Same with uneven matched engines. I ran three GP35s together and with one of the units up in front everything was running smooth. With the same unit in the middle or last it wanted to turn. I also need to check that everything is leveled correctly. I didn't have at all as much problems with the crossing before I started to build the scenery with the small climb leading to the small bridge (that I of course want). I still think I want to grind off a little bit of the tip (green arrows) that I think catches the wheel when it is coming sideways. And of course I would like to build a handlaid 45 degree crossing but that's a whole new level of challenge.
Be careful with grinding anything on a Marklin crossing or switch. Because the non Marklin wheels are not running on the designated path via the flanges, the wheel may falls into the extended, unsupported area. I would try to shim the bottom of flange ways to adjust for smaller flanges.
