R C & G

29


When I went looking for photos of the earliest bits of construction of this locomotive I came up empty handed. I could have sworn I took some but so far no luck finding them. If I do I'll add them at a later date.
Probably the earliest photo I found shows the extended axles that I made for the Aristo gear boxes. It also illustrates the method I use for attaching the drivers to the axles that allows adjustment of the quartering. I can't take credit for the method as it is the result of some communications I had with Barry of Barry's Big Trains, maker of the famous bullet proof replacement drives for Bachmann Annies. He never supplied a drawing and what you see is my interpretation of his verbiage. Since I've never seen one of his drives I can't say how close I came to replicating it but it works great so I'm sticking with it. The axle is drilled for dowel pins. Note they do not need to be offset like I did here. Their location is critical as the will ultimately determine the gauge of the drivers when assembled. Some adjust can be made by altering the dimensions of some of the other parts but it's no fun to go back and machine them a second time so it pays to measure carefully and do the math correctly.
After the dowel pin the next piece, machined from brass, has a slot milled in the back side of it that fits into the dowel pin and keeps it from rotating on the shaft. The hole through the center is a slip fit. The smaller diameter portion of this piece fits into the back side of the driver. The length of this section is such that it doesn't quite extend all the way to the outer side of the driver face. The last piece of the puzzle it a brass washer that fits into a recess bored into the face of the driver. The driver is then placed on the axle bushing, the washer goes on next then the socket head cap screw goes next. When the screw is tightened  it clamps the driver to the axle bushing by lieu of the fact that the center part of the bushing is slightly short of the driver thickness at that point. While initially I wasn't sure this would be adequate to hold the driver in quarter, so far testing on rollers has shown it works fine.


The next photo shows the driver mounted to an axle. This is the center axle so it doesn't have a gearbox but the plain axle is done the same way. The clamping surface seems to be large enough to keep it from slipping when the screw is torqued down snugly. Also note this center driver has been fitted with an aluminum tire to bring it up to the same diameter as the other drivers. These are from a Bachmann Annie. The center driver on those is made smaller to help keep the others on the rails when going over grade transitions. On this locomotive the center driver is sprung so that is not an issue.

So far this is the earliest photo of the frame I've found. At this point the drive has been installed. Since the gearboxes have ball bearings for the axles I just used friction bearing in the frame. I don't see this locomotive ever accumulating a lot of mileage so they should be just fine. The drive is similar to what I used in # 14. The two gear boxes are tied together with a length of 4mm Allen wrench which is a perfect fix for the hex shaped holes in the gearboxes. The frame was machined from 1/4" brass bar stock and assembled with flat socket head cap screws. The cylinder assembly was done similar to # 14 as well only in this case I used Delrin instead of aluminum. The cylinders were turned on a lathe and attached the center section. The cross head guides are made from hollow square tubing with a short length of brass rod that just fits inside the square tubing and is silver soldered in place. This then fits into holes drilled in the face of the cylinder. The main rod is from a Bachmann Annie that was beefed up by adding some styrene to the top and bottom edges of the rod. The cross head guide was machined from brass. The motor is a standard Pittman motor and drives the main shaft through a timing belt. I get some additional gear reduction this way and it provides a smooth quite drive. The frame is sitting on full size (1/24 scale) drawing of # 29's sister engine # 30 which was identical except for the valve gear.


The next photo shows a different angle. It shows the bearings for the center axle which ride in a slot in the frame and the method I used for spring the center driver. The round shaft between the center axle and that front gearbox has holes drilled in it for a pieces of piano wire which is held in place by a set screw. This wire extends back and fits into a hole in the bearing block for the center axle, By rotating the round shaft one can adjust the amount of spring tension on the axle. Once set the round shaft can be tightened in place by set screws in the frame. The shaft has a hole in it that is used to turn it to adjust the tension. The driver centers shown behind the locomotive have had new counter weights scaled from the drawing over laid on the original weights.


Between the photo above and the one below several items have been added as indicated by the red arrows. While I had no intention of duplicating the complete Stephenson valve gear I did desire a way to add motion to the valve actuators, something that is seldom done even in large scale.


The next photo shows how this was accomplished. Two eccentrics were turned from Delrin and press fit on to the center axle. The eccentrics have a groove cut into the circumference and two very simple cam followers were made from brass bar stock and piano wire. The wire rides in the slots and their up and down motion is transferred to the valve actuator shafts by yet another piece of piano wire. All of this needed to take into consideration that the center axle can move up and down. The larger diameter disk has magnets mounted in it to provide chuff triggers.


The next two photos illustrate the range of motion of the valve actuators. In reality not all that much but enough to provide some interest.



The next thing that was added was the pilot with coupler. The pilot is all made from brass and uses actual hex head fasteners. The foot boards are wood.

   
The most current progress on the locomotive is making a template for the mounting plate that supports the back of the cross head guides. It still needs some additional shaping at the time of the photo.

Some basic work has begun on the boiler. The boiler is made from several PVC pipe couplers glued together with short lengths of pipe then turned on the lathe to level it all out and achieve the desired diameter. This was done as the diameter I needed fell between common pipe sizes. The smoke box will get a thin styrene overlay with rivets embossed on it. The headlight is a stock Bachmann item, the smoke stack which still needs a base was turned on the lathe as none of the available ones I had were the correct diameter, shape and length. The domes are reshaped Bachmann items. The large steam dome was turned from Delrin but the base came from a Bachmann dome. The bell is an Ozark casting. The rear support for the boiler is just a few pieces stacked to hold the boiler level for the photo.

Additional detail parts have been made. The air tank uses Ozark ends on a turned piece of Delrin and the brake cylinder is a one piece lathe turning from Delrin. At the bottom of the photo is a smoke box front made from the end of a PVC pipe cap.

The last bit of the frame has been added in the next photo. That's where progress on the locomotive stands as of the posted update date below.

This locomotive also needs a tender. Starting with the frame I found that a Bachmann Annie tender frame was almost dead on for length as shown in the next photo. It was clamped in the mill vice and all of the various protrusions that would be in the way were milled flush with the floor.
The bolsters needed to be re-positioned so any detail that was in the area where the bolsters needed to be was also milled away.

After that the old bolsters were milled away, new ones salvaged from an old car under frame were glued into the new positions.

One of the potential issues I faced was trucks. I needed a truck with a 56" wheelbase and most of the trucks available were too short in that dimension. Fortunately another modeler had a set of tender trucks from one of the 1/20.3 K series locomotives that had the correct wheelbase for 1/24 and was willing to part with them for a reasonable price. The only thing I needed to do to them was lengthen the bolster to widen the gauge. This was done with a couple of turned brass spacers as shown in the photos below. I had to tap the original bolster screw hole for a longer and non metric screw. The modification has the benefit of providing some equalization.



The wheels came from Northwest Shortline. They were sized to be used as replacement 42" wheels in 1/29 scale which works out to 33" in 1/24. I had purchased a lot of these for use on 1/24 scale standard gauge cars. The photo below shows the reassembled truck with the new wheels. Unfortunately NWSL has recently announced they are closing so unless someone buys the company and continues the line these will no longer be available.


The next photo shows them mounted under the tender with one of my standard narrow gauge trucks for reference. While the drawing shows Bettendorf style trucks, photos, including the one at the top of this page, show # 29 came with archbars.

The tender shell was built up from .062" thick styrene. The front of the water legs were made from PVC pipe. The bottom of the pipe pieces has plug that is drilled and tapped to provide a way of securing the front of the shell to the floor. At the back end a double thickness of acrylic was shaped to match the back end of the side walls and was drilled and tapped to provide a way of securing the back of the shell to the floor. In the next photo the various items that need to be installed in the shell have been placed to make sure they all fit. The speaker will have a wooden box placed over it to improve sound quality . The other items left to right are the battery pack, Revolution receiver and Phoenix sound board.

A piece of .020" styrene sheet was cut to fit the top and glued in place. This is currently where the tender is in the construction process. The next step will be to sheath it with a layer of thin styrene that has been embossed with the hundreds of rivets as shown on the drawing. This process is on hold while I attempt to get my semi automatic rivet embosser working as is discussed in the article posted on the Articles Page here.


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Updated  4/16/19