I have an 11 year old Mikado from Kato and the electrical pickup is becoming more and more a problem. I only get continuity from the tender trucks and none from the loco drivers. I bought a bunch of the newer drivers from Kato several years ago but never got around to installing them. Truth be known I'm scared to death about messing around with the running gear. Can anyone who has done this conversion give me some advice as to how to go about it without ending up with a roundhouse queen? Does the running gear have to be taped in position before removing the old drivers or is there some other secret? Any help would sure be appreciated. ...Tom
Hi Tom We have done many Mikado replacements. It is not too hard but does take time and patients. We don't tape anything in place but do completely dissemble the loco, drive and side rods. Care needs to be take when reassembling and reorienting the piston rods and quartering the wheels. The rod pins have a tendency to loose themselves so care needs to be taken when removing and reinserting them into your new drivers. A good idea is to take pictures of before and then as you start to take the loco apart.
Tom, The following is Kato's procedure for changing the traction tire: http://www.katousa.com/N/Mikado/maint/ttire.html It is quite easy. Harold
Vince, I believe you are referring to the GS-4, of which you are exactly right. Correct me if I'm wrong but the Mikado traction tire does not connect to the piston rods. Harold
I don't believe Tom is talking about the traction tired driver. My understanding is he wants to know the procedure for replacing all of the very poor conducting drivers from an early production Mike.
Assuming you have in your possession the Kato revised driver set (all four), the order in which they are placed is as follows: 1. The first (most forward) driver set has no gear. The wheels have a hole opposite the counterweight to pin the connecting rods. 2. Driver sets 2 and 4 are geared and have no holes opposite the counterweights. There is no necessity to pin the connecting rods to them because the gears enforce the correct rotation of the wheels with respect to Drivers 1 and 3. 3. Driver set 3 wheels have holes opposite the (larger) counterweight. This is the driver to which the main rods, eccentric cranks, and connecting rods are attached. The wheels are quartered from the factory (I do not know if it is possible to make adjustments or if slight misalignment is even possible). If you align the counterweights in their proper orientation on one side, the other side is automatically correct. You cannot insert the axles into the frame incorrectly - the gears allow only one fit. You must align drivers 2, 3, and 4 before you do anything else. Once you have done that, the freewheeling front driver will automatically align properly with the other drivers when you add the connecting rods and pin them to driver #3. Once you have the four driver sets installed, you then install the steam cylinders, crosshead guides and main rods, and the valve gear. You have already pinned the connecting rods to the front driver set and they are dangling, waiting to be connected to driver set #3. Getting the main rod, connecting rod and eccentric crank attached to driver #3 is fairly straightforward, except for the proper orientation of the eccentric crank. That can be somewhat deceptive. I do not know how to explain it. You will know if you made a mistake when you try to run the engine and it binds up, and it looks as though you did nothing wrong during assembly. The valve gear and side rod motion have nothing to do with the propulsion of this model. They are strictly "along for the ride". I have a disassembled Mikado that I am currently working on and I cannot pinpoint where the bind is. The loco runs just fine with the valve gear and side rods removed, so the bind is in the positioning of the eccentric crank. I do not see how it can be anywhere else. I have a suspicion, now that I think about it, that the eccentric cranks should be exactly opposite each other even though the wheels are quartered with respect to the opposite side. That's the hard part of driver replacement. Other than that, it is tedious work but rather straightforward.
