Small-Scale Live Steam Locomotives

Additional notes on the Aster USRA Mikado

by Marc Horovitz (Editor, Garden Railways magazine)

If the Mikado is your first Aster kit, there are some things you should know. I strongly recommend that you read the excellent directions word for word, and don't try to jump ahead. This will only lead to tears. When in doubt, the drawings should clear things up. It is of vital importance that all moving parts be free running. While assembling the kit, make sure this is so. This may involve filing, sanding, and drilling. When the chassis is together, the wheels should rotate freely, with no binds or rough spots. If there are any, now's the time to get rid of them. Steam-tight connections are also critically important. Use gasketing compound. You can use the white silicon provided with the kit. I prefer Loctite Gasket Eliminator. Whatever you use, use it sparingly. It takes only the thinnest coat to make a good seal. The smokebox must be air tight for the fire to draw properly. Use the white silicon and follow the instructions, making sure that there's plenty of sealant in there. This is a sticky, messy job, but an important one. Fit the smokebox while the sealant is still wet. If the silicon has cured, you might have trouble getting everything to go together properly.

What follows is what I found by way of errors or omissions in the instructions, as well as additional work that I had to do to make things right. I've listed them by assembly number and note number. This is not intended to be a definitive list or even an accurate one -- these are just notes based on my own experience. Your experience may vary. I invite you to submit any additions or corrections you may run across. As Aster kits go, I found this one to be remarkably trouble free.

Note 4
The axle boxes on my engine were tight in the frames. I filed the frames a little for a better fit, mostly just removing paint. A little oil helps here. When attaching the 1-12 horn stays, I found that the screwdriver didn't like to rotate while fitting between driver spokes. Filing the sides of the blade even with the shaft encouraged it wonderfully. Note 5 The coupling rods, when in place, caused the wheels to bind slightly. The only solution I could think of was to drill them out, which I did, removing probably .001"-.002". This allowed the wheels to turn freely.

Note 4
Test fit the slide bars in the slots in the crossheads. I had to file the sliding surfaces on both the slide bars and the crossheads to achieve a good running fit. Notes 7 and 8 Do 8 first, then 7. Note 11 When attaching the 2-19 valve-spindle crosshead, note that these are LH and RH parts. One hole is threaded and one is through. The threaded hole goes to the inside. Note 12 I filed the bottoms of the valve covers flat for a better fit.

Note 1
The front and rear motion plates required a little filing to fit well in the frames. Note 2 Mount one cylinder, then fit the steam pipes, then fit and mount the other cylinder. Attach the cylinders loosely until all is in place and the cylinders are properly aligned. Then tighten the H1 bolts firmly.

Note 1
I filed the die blocks flat on both sides for a better fit and better action. The radius rods required some straightening and some filing for a good fit. Note 3 The upper hole in the combination lever required opening out a little for the 4-6 pin. The second sentence in note 3 is wrong. The front end of the radius rod is located over the pin beneath the top hole in the combination lever. Together they are slipped into the valve-spindle crosshead and attached to it with the 4-6 pin. The sides of the crosshead hold the radius rod in position. The front end of the radius rod required filing to fit. Note 4 The crosshead holes required some cleaning up with a small round file. Note 7 The fork end of the eccentric rods needed some filing to fit.

Note 1
The instructions say to rotate the wheels until the crank pin is at front dead center. It should read "rear" dead center.

Note 3
Install all of the brake-beams (6-5) except the rear-most. Save that one for later. Note 4 Do this step after step 1. Then do the air test. After it is successful, then do steps 2, 3, and 5. After a successful air test, remove the lubricator and set it aside for later. Don't worry about properly bending the lubricator line to fit at this point. You can't do it.

Note A3
The steam pipes, 7-9 and 7-10, must be prebent to a good fit before attaching them. Don't attach them and then expect to bend them to fit. Note B4 The gauge glass must be slid up through the bottom holder, then the various gaskets and nuts slid over it, then the glass slid into position in the upper holder. Make sure there is an equal amount of glass in both holders when tightening the nuts, and don't over-tighten them. Put the red line on the glass toward the front of the engine, immediately behind the backhead. Note B5 The illustration shows the pressure gauge facing the rear of the locomotive. In this position it fouls the throttle lever. Turn it sideways to face out the window. The pipe can only be roughly bent at this stage anyway.

Note 5
The note says to file the bottom face of the compressor. This should read "file the back, or inside, face" of the compressor. The compressor in my kit was already filed. Don't try to use an H3 bolt to attach it. It's too short. I used an H5. The running boards can also be fitted at this time.

Note A2
Open out the middle hole in the arm with a #21 drill. Mount the arm to the reverser first, then mount the reverser to the bracket. Add the stanchions after step 3. Use a wire through the hole as a handle to screw them in. Note B4. Pay special attention to applying packing compound to the threads. I call your attention to this step because I missed it somehow. The result at first steaming was no pressure in the boiler, a smokebox full of water, and an excruciating partial teardown to remedy the problem. I strongly suggest that you let the packing compound cure, then do an air test on the boiler, brushing all joints with soapy water to check for leaks. Now's the time to fix them, not later.

After step 1, reattach the lubricator to the steam line. Temporarily fit the boiler so that you can properly bend the lubricator line to fit. The paint chipped off mine when I bent it. After step 2, attach the lubricator to the running board, making final adjustments to the bends.

Note A1
Before going on to step 2, attach parts 12-6 and 12-8 with pin 12-3.
Note B1
Attach the bell before step 2.
Note B3
I had to open the holes forward a little with a small round file, making them ovals, before the smokebox-front holes aligned properly.

Note 1
The instructions call for 30 strands of wicking. The wicks will seem quite loose with this number, but stick to it. I packed mine more tightly and had to go back and unpack them because the fire was choked. The wicking appears to be asbestos. Soak it in meths or water before handling it to prevent asbestos dust in the air. I cut the strands with a razor blade.
Note 2
The cutouts had to be opened out a little with a file. Note 3 After the wheels are in the frames, add the back plate (13-15), then the dummy side frames (13-13). After step 3, add the last brake beam (6-5) and brake shoes.

Note 1
There is an error in the text. The last sentence refers to a PS-2 O-ring. This should read "PS-3". The drawing is correct.

This article is copyright by and is property of Marc Horovitz.
Web site compiled and © copyright 1999 by: Vance R. Bass. All rights reserved. Please use any and all information contained herein for your hobby enjoyment. If you're going to make money from it, talk to me first.

Last updated: 13 December, 1999.