I've just bought a new mikado, my first steam engine (bit of a Christmas present that finally arrived in the mail) I'm having a bit of an issue with it, and I think I've finally tracked it down... When the locomotive gets into a curve, or sometimes when hitting a turnout, the front driver shifts to the side and the thing jams hard. Okay, I don't know the names of the parts, but the knobby part that is attached to the wheel (pointed to in red), jams into the end of the rod (pointed to by the yellow arrow). I gently tried prying the side rod away from the drivers, and at first I thought it worked, I nearly went through my entire layout, but then on one particular turn, it jammed again. At this point it's usually jammed hard enough not to be able to move forward or reverse. I can unstick it by pressing the driver back to centre. I'm hoping someone with experience with steam locos in n-scale has a nice fix for this!
The red arrow is pointing to the crank pin, which is hitting a riveted joint of the valve gear. Can you press the crank pin further into the driver? It looks like the crank pin has about twice the thickness of the drive rod sticking out of the driver. I can't compare the driver on the opposite side since it is not in the photo. Just don't press the crank pin in so far that there is no clearance left for the drive rod to float a little.
Here's one of my units: You can see that there is perhaps 50% of the rod thickness showing on the crank pin on one side, and less than 25% on the other.
Yes, I see what you mean. I ran the locomotive on my track slowly until the crank pin was at the bottom of the wheel to get better access. The rod has quite a lot of play on the pin, a lot more than the other side. I can't figure out how to push it in, doesn't seem to move. The end of the pin has a hex form to it, maybe it needs to be twisted?
I agree with rasputen. It is amazing how finicky these crankpins and rods can be to keep from binding. Occasionally, if it won't stay put, you may end up pulling the pin and putting a tiny dot of 'red loctite' in the hole to keep the pin locked in.
Item 93 is what needs to be pushed in, now just how to push it in is the question, lol. I'm trying to be gentle, everything looks really fragile. On my loco, that pin has a hex head, not round like shown in the exploded parts diagram. But it definitely is the part that is hooking into part 92 and jamming the whole mechanism during the start of a turn, when the wheel is pushed all the way to the side... that wheel set (driver set?) has a lot of play side to side.
I haven't had to disassemble any of mine, so I can't help you much. They are definitely fragile so be careful! I'm not sure where you are located but you can also contact Broadway Limited. They have excellent service.
Can you get a small needle nose pliers in there to gently "squeeze" the pin in farther? There is also the possibility that one or both drivers are not pushed onto the axle far enough and allowing too much side play. Doug
I tried squeezing the pin in with pliers, but it doesn't move. I don't feel comfortable disassembling anything for now so I'll send an email to Broadway Limited support, see what they say.
I tried rotating it, but it didn't move. Used quite a bit if force too. I've sent support an email and will wait for a reply. If they want me to send it in, not sure if I should just return the item where I bought it. Either way, shipping and import duties will have me lose quite a bit of money. Sucks because otherwise this locomotive is beautiful and runs really well (so long as it doesn't need to turn right!)
If you can, return it to the place where you bought it from and get a refund or exchange. Much quicker resolution. If you chose exchange, see if they can test it for you before giving it to you. If you send it to BLI, it will take weeks, not to mention what you said about shipping and import duties.
Looking again, the shoulder on the hex-head pin is too deep if it is in all the way. As far as I'm concerned, a buyer should NEVER be out any money, other than the original purchase price, if a product is defective and must be shipped for repair or replacement. I always negotiate, even if the seller claims the buyer must pay shipping for returns, and the seller usually will back down and pay shipping. Doug
So, turns out I contacted Broadway Limited, and they mentioned looking at three things before sending it in to get it running right: "The first thing I would look at is whether or not the crankpin is pressed all the way into the wheelface. If that checks out, then I would see if it is possible to bend the crosshead guide/valve gear linkage away from the chassis a bit to get a bit of clearance. Also, check to make sure that the wheelset is in gauge (if it's a bit wide in an NMRA gauge then that could be a potential problem there)." Very pleasant, and I already knew the crankpin couldn't move in further, the wheel gauge checked out, and I gently tried to move the linkage. Finally, I did remove the four bottom screws and remove the bottom plate to look at the axles. Lifted the problem wheel set out a bit, then just replaced it and closed it up again - didn't want a mess of parts on the table So now, miraculously, the engine runs flawlessly. I have a folded dogbone layout and have since run it forwards and backwards, slow and fast throughout and not one hick-up (maybe 40-50 minutes run so far). Even tried it on a Kato unitrack loop with 9 3/4" radius and ran super well there as well. So all in all, problem solved, somehow. Maybe I knocked something back into place when I took off the bottom plate. I won't question it further Thank you everyone for your help!
When I disassembled my T1 it appeared that the axle bearings are very finicky in their placement in the frame. So, maybe you successfully did get the bearings back into place! Sweet!!
When I disassembled my T1 it appeared that the axle bearings are very finicky in their placement in the frame. So, maybe you successfully did get the bearings back into place! Sweet!!
Now we know where to send out BLI steamers for repairs! . I'm sure your turn around time will be quicker. Glad you got it resolved.
