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Where to start. You will need to find a copy of the Ntrak Narrow Guage Handbook for pictures, and my copy says fourth edition. (I believe there is a fifth edition on the editing table now.)

Next you will need to locate several old MRC locomotives. For the shell you will need a couple of C420's. At least one of them must be the single powered truck type. For the trucks you will need at least two sets of trucks from an RSD-15 or RSC-2, Mine came from an MRC RSD-15. IF you can find one, get a Kato U30 cab shell from which you want the rear cab doors.

Preparing the parts. The first step is to take apart the C420. Remove the shell from the chassis. Remove the trucks from the chassis. Remove the motor and electrical wiring from the chassis. With an Xacto knife carefully remove the handrails from the side of the body shell and the porch at front and rear.

Preparing the shell. First mark a line all around the shell one scale foot above the deck of the running boards. Next make a cut on the rear portion of the long hood by cutting down 26 feet back from the cab and just behind the door hinges below the two small grill panels. The cut should be just flush with the running boards on both sides. Next cut the body shell away from the running boards, flush with the top of the running board deck. Then remove the grill with careful cuts along the outside edge of the rear edge of the frame and the do the same at the forward edge of the frame. For the final cut from the open end of the rear part of the shell cut along the top edge of the louvers to remove the grill in one piece from each side. You need the frame with the louvers. Now cut the bottom foot off of the rest of the shell at the top of the lower hinge on the access panel doors on the shell. Make this a straight and smoth cut as you need the shell later. Now check your work: the nose should be 4 feet tall and the hood part 7.5 feet tall. Next shorten the nose by removing 2 feet from it. You'll have to decide where best to do this. At some point in time you want to remove all the detail from the sides of the cab and the nose, the roof of the cab and the low hood. Fill in the Headlight holes with body putty and smooth the contour there also. Next cut is 26 feet back of the cab on the long hood. Make your cut just behind the door hinges. Now remove the details from above the doors between the two sets of grills, then remove the roof details on the long hood. Now cut and remove one of the three sections from the grills you removed from the rear of the long hood. If you are careful in removing the third section of the grill you can use it later. If not you will need the grill from the second C420 later. Dress the side of the grill so they are the same width and the top and bottom sills so they are the same height. Now reassemble the rear of the long hood by inserting the grill at the end of the long hood and flush with the walkway on the shell. Now you need to file to fit the rear part of the hood to come forward over the new grill to fit around the new grill which is only two panels wide now. When done, the rear section over the lovers must be flush with the roof line and the lower edge where the walkway will fit.

The shell should be just short of 47 feet from end to end and with the running boards in place, the length should be 52 feet over the platform ends, and 53 feet over the coupler knuckles. When lining up the running boards to be glued into place on the shell remember the following. The forward edge of the rear ladder is in line with the rear of the hood, and the forward edges of the ladder at the front of the locomotive are in line with the forward edge of the hood. This means that at the rear the ladder looks straight across the rear platform of the engine while at the front the platform extends forward over the plow and around the front of the hood. The trucks on the underframe are located such that at the front of the locomotive the front edge is in line with the rear edge of the forward ladder. At the rear of the locomotive the trailing edge of the rear truck is 18 inches ahead of the ladder. You will have to extend the walkway forward of the low hood on the locomotive. I attached the rear portion of the walkway to the shell first, cutting it off just in the area under the cab. Then I trimmed the forward section of the walkway to fit under the locomotive with the joint below the cab floor. I then left this part to strengthen and turned my efforts to the chassis next.

The chassis has a large round hole just under the motor and this is the area where the previous motor electrical connections were made. Remove the latches used to hold the shell down on the frame. Cut them down level with the outside of the beam on which it sits. Next cut down the outside of the frame starting beside the tower and working along the frame into towards the hole inside the chassis. Repeat this for the other side of the frame at the gear tower. When you are done you should be able to pull the gear tower with its piece of frame away from the rest of the chassis. Move the two parts back together, adjusting the truck centers to approximately the correct spacing of 33 feet, testing the mating of the frame to the shell and when satisfied that the distance is correct clean up the junction of the two pieces by cutting the piece with the gear tower to flatten the end off where the hole used to be. On the inside of the frame extend the hole towards the rear of the chassis until you can insert the piece of the chassis with the gear tower and maintain the new truck centre to centre distance. Next slip the pieces of the chassis under the shell. The piece that does not have the gear tower goes towards the nose and the piece with the gear tower goes to the rear. next glue with liquid styrene cement the two pieces of the frame together. Next mill out the frame to allow for a Kato replacement motor p/n 11501 and mount the motor into the chassis using silicone to form the shock mount and hold the motor. The motor is mounted with shims below it glued in place with liquid cement. The shim rails elevate the motor so that the shaft lines up with the motor shaft, with a gap of about 1/8 of an inch or 3.5mm. The motor has a round side so my shims are two rails that hold the motor in place in its silicone mounting. For a shaft coupling use a piece of surgical tubing with 1mm inside diameter 11 mm long. You have to cut off the motor shaft at the brush end as the motor is mounted with the brush end away from the gear tower. Next test fit the old trucks in place and trim the fuel tank sides attached to the frame to allow the trucks to swing freely. Do not overdo this, cut just enough to clear because when you narrow the trucks they will have more clearance.

Creating narrow gauge trucks from the standard gauge trucks of an RSD15.

We will start with the power truck first. Turn the truck over and observe that on one half of the truck chassis there are holes for the gears and on the other half there are none. The first thing to do is the take the truck apart. slip the side frames off of the truck. Now remove the wheel sets and pull the wheels off of the axles. Carefully remove the pickup wiper from the half of the truck which has a solid bottom and no holes for the gears on the axles. Next look for the two holes that match the pins on the other half of the truck, you need to drill these holes out through the side of the truck frame as the pins will fit into the cover when it is modified. Now use a razor saw to remove the end, top and bottom flange leaving just the side of the truck and the side of the gear tower. Try not to remove or damage the raised strip that extends up and down the side of the frame inside the gear tower. When done take a file and smooth the edge down flush with the side. I hope you have a Dremel tool for the next job. It is to shorten off the plastic gear axles to the new dimensions. The axle with the smaller gear on it you will see has one side longer than the other. The long side you will notice has three diameters on it: one for the wheel, one for the opening in the side of the truck and other one to hold the axle in place inside the truck and keep the gears aligned and in mesh. The short side has two diameters and will not be altered. Place the short shaft into the half of the truck with the gear holes in it. now mark the axle at the point where it projects beyond the truck frame. Now place the short end of the axle into the chuck of the dremel tool. Turn the Dremel tool up to the highest speed. Now comes the hard part. Use an Xacto knife as machine tool cutter to cut the largest diameter down in size and to shorten it to the mark you made earlier. Do this by making sure you have a new blade in the knife and by laying the blade on the running part of the axle. At first have the blade in line parallel with the gear on the shaft. Now tilt the blade to put the blade edge on the running shaft and tilt the blade slightly towards the step and slowly bring the blade towards the step. Go easy as it does not take much effort before you are cutting away material on the shaft. Run the blade up to the mark. Remove the axle from the Dremel tool and place the small end into the unmodified truck half and place the modified truck half over the newly turned-down bit of axle to ensure it just fits into the hole in the side for the axle. Turn the axle by hand making sure it spins freely. When you are satisfied with the fit, mark the long end extending through the side frame. Now you are going to reduce the second diameter. This one is more critical than the first because this is the one that must press into the wheel again to hold it on the axle. Use the same method as before to reduce the middle diameter and move the step back to the mark you made while trial fitting the axle into the truck. When you are done see if you still can fit the wheel onto the axle and move it beyond where it was positioned originally. Hopefully it is still a tight friction fit. Do the same thing for the second geared axle. On the idler you are going to do the same thing again. There is only one diameter that needs to be reduced and the process is just like the other axles. On the tower gear we are going to remove a portion of the gear spacer to allow it to fit back into the tower.

Reassemble the truck. First insert the wiper into the modified side frame and bend the tab up out of the way so you can bring the halves together. Take the unmodified truck half and place the unmodified end of the axle into the truck frame and push a wheel onto the axle and repeat for the other two axles. Next place the modified side on over the axles. Push the wheels onto the axles making sure the wippers are formed correctly and touching the back of the wheels on the two end axles. Check the with a wheel guage for the correct distance between the wheels before you cut off the axle extensions. Make sure the spring on the idler is also replaced in the modified truck. If this is missing you will find you pickup poor and the engine will derail going in the direction which places this axle as the lead axle on the truck. On the forward truck it does not matter which half of the truck you modify. Modify the axles in the same manner as before, only this time there is only one diameter to modify. Do not forget to replace the pickup wiper and how to modify it to fit the truck again. Also the fix the spring on the idler to keep it from floating in its elongated hole.

Truck side frames are modified next. Remove the coupler that extends flush with the end of the frame. Look inside and you will see two lugs that hold the side frame in place. Now that the truck is narrower, you have to take a piece out of the this section and glue the two sides back together. Use ACC to glue one half of the side frame to the truck first and then glue the remaining half of the side frame to the half on the truck.

Make sure the tower gear fits into the tower on the power truck. Run the gears by hand and make sure thaere is no binding and they run free. Next you need two .015 shims to go into the tower on the frame, between the tower on the truck and the inside of the frame tower to keep the truck centered in the hole. The spacers are held in place by the tower gear axle which goes through the frame as well. These spacers were made in an oval shape about 3 scale feet long and 1.5 feet tall, with a hole in the center for the axle to pass through. Next make sure the truck will articulate properly in the tower and lubricate it with light oil and teflon powder. Then make sure that none of the frame was interfering with the movement of the truck. On the forward truck glue a small piece of brass tubing into the hole for mounting the truck to the chassis after opening it up across the full width of the truck. Use a file to dress the tube flat with the top of the truck, then place a .010 washer on top of the hole and ACC it onto the top of the chassis and use a 1/72 round head screw to hold the truck in place in the chassis with a nut and brass flat and lock washers on top. Again check that the truck articulates properly and freely. Next complete the wiring from the trucks to the new motor and test run the motor and gear train to the narrow gauge truck to make sure it runs well. Lubed the whole thing while it is running on its back with test leads attached. Break it in as it is with a minimum load.

Mate the chassis with the shell and modify the weights to fit the new shell. For the pilots cut .015 sheet styrene to fill the space across between the forward and rear ladders. On the rear pilot mark the coupler pocket height using an Nn3 coupler height gauge and cut a pocket for the Micro Trains Nn3 coupler to fit into. On the rear pilot use a piece of .030 styrene glued from behind flush with the top of the hole as a mounting block for the coupler using a 00-90 screw. At the forward end cut two pieces of .015 styrene sheet to plate across the front of the pilot, the glue them and let them set over night. The next day using a file mark the center of the pilot and two feet on either side and then use a file to shape the two layers of .015 on an angle so that the pilot is flush with the ladder and full depth at the lines 2 feet off center. Now mark the coupler pocket and cut it out using a drill in the corners and around the perimeter and then using files to finish it. Next fabricate a large snow plow out of the aluminum pieces that come with a 1154 Micro Trains coupler conversion. The plow is four feet straight across the bottom at the center and then rises 1 foot to the outboard edge. The bottom edge of the plow is a 1/2 foot above the rail height and comes up to the bottom edge of the coupler pocket at an angle. The wings on either side of the coupler pocket rise four feet high and then curl out and roll forward. The plow extends about 6 inches beyond the ladder on either side of the pilot. When done the height of the plow should be shortest by the coupler pocket with the most forward curl and almost four feet tall at the ladder edge with only a small curl. The plow should also be pushed back into the chamfer of the pilot. Once the plow was in place push the coupler into the pocket and drill up from the bottom of the pilot a 00-90 tapping hole, then tap it and countersink the hole. Use a small screw to hold the coupler in the pilot. Make sure the screw is countersunk so it does not catch anything between the rails.

Now you are left with painting and putting the handrails back on.

Garth Hamilton
Ontario, Canada
nn3@ve3ho.com

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