Next up is an I-7 built from a Athearn/Roundhouse old time 2-8-0 I picked up at the same show I got the 4-4-0 which is now the D-8. There are a couple ways to do this class of engine. There is the low set key hole firebox boiler version, the higher set wagon top slide valves, and the wagon top with piston valves. They are not highlighted very much but there were quite a few of these engines roaming the system.
To keep in my 30s-50s range I went with doing one of the later style versions of the class. Originally planning on keeping it slide valve, I changed my mind to do piston valve cylinders, mostly because I have not done a slide valve to piston valve conversion, so it was something new to try.
With all the variation in the large class this is basically what I’m going for.
This is the untouched Roundhouse engine.
The engine was quickly broken down to what is needed for the project.
Piston valve cylinders lean in a little on this class so the slide valve casting was ground down a bit on the outside then the inside of the box on top of the main cylinder. The saddle for the boiler was also ground down in preparation of an extension that will lift the boiler up.
In the picture above you can see the base template for the frame work in the conversion. This was done be placing the cylinders face down on a piece of .010 styrene and tracing the cylinder. The top piston was traced using the smallest tube stock I had with right side of the circles being on the same line, then I drew a connecting line for the
love, love, love these build threads. I learn an awful lot from your descriptions and from the photos. thanks as always for taking the time to do this.
These I-7’s have always fascinated me, partly because their appearance is such a departure from the expected RDG Camelback design with a Wootton firebox. I understand one or more I-7’s was sold to the Ironton RR in later years.
Yes the Ironton had examples of both the I-7 and I-8 class. The Reading only had a few non wooten engines the I-7 being the exaple they had the most of.
rrinker, the more I do the faster it goes but I also had a bunch of projects between show and rediscovering some things when moving. So I have benn kind of working non stop for a couple years haha.
The I-7 had 55" drivers, had you considered using an 0-8-0 as a starting point to get the larger drivers? The I-7, I-8, I-9 all used the 55" drivers for a large portion of the classes. Unfortunately the model manufacturers tend to do either 50" or 62" driverson 8 coupled engines. The only engines I’ve seen with the 55" drivers were USRA 0-8-0’s (or brass engines). The Roundhouse 2-8-0 is a nice starting point though.
Though the driver size is right, thats about the only useful thing on a usra 0-8-0 for a I-7. The only mass market 0-8-0 is the proto 2000 one and the way they are built they are quite a pain to make in to much else, plus those drivers are 50". Also the cylinders would be big, the boiler would sit too high, wrong counter weights on the drivers, the motor is too big for a smaller boiler, etc. The drivers on the roundhouse engine are listed as 52", big picture 3 inches in HO scale is miniscule.
Also the majority of I-8s were 61.5" drivers, and there was a later sub class of I-9s that were fitted with larger drivers in the 1900 number range.
I’m not so sure about the driver size used on the various scale models, but a prototype USRA 0-8-0 typically had 51" drivers, not 55". To get drivers in the 55-57" range, I think you probably need to find a brass engine representing an appropriate prototype. Santa Fe “1950” 2-8-0’s, U.P. “6200” 2-8-0’s and a number of others would fall into this category. Casey is right when he says 3" is miniscule in HO. In general, it’s easier to justify smaller drivers than overly large ones.
The putting a fire box on the tube is not really different then putting a wooten firebox on, the frame goes trait down from the boiler instead of getting wider.
This one I tried something a little different and set the bottom for the firebox, or mud ring, before wrapping the sheet of styrene over the frame. It was easier to set next to the reused metal weight without the sheet there. Once the wrapped sheet was in place and trimmed the jacketing layer was added on the rest of the boiler to match the height of the firebox sheet. The hard edges of the firebox were then sanded.
The stack and domes start with the main barrel shape. The stack is a piece of tube stock the domes were pieces of .010 coiled up and glued to itself, with the seam being sanded smooth.
While the dome bases were drying I made the steam delivery pipes from tube stock.
The domes were trimmed down and capped with 2 layers of .040 styrene. Those layers were shaped by sanding, the steam dome on the I-7s were not a full dome shape on the top, it was a flatter dome with a harder angle on the outer ring. Once the tops were shaped putty was added at the bases and allowed to dry over night.
The bases were then sanded to slope into the boiler.
I don’t really plan on it, between having a large older collection, picking up cheaper old engines, and not having to get electronics which makes projects much cheaper and I think easier to do, not having to work around some stuff crammed in. I also really have no interest in model sound, but a bulk of the built roster is DCC ready and only one doesn’t have the motor isolated being an original open frame motor. If I got tied into a club I would consider putting decoders in which I doubt would be a problem. The shells are no more fragile then detailed mass produced models. It would also just be wires running to the tender to stash the decoder.
The boiler bands were next to go on except the one towards the front of the firebox, I wanted to get the running boards placed first. These are strips cut from .010 styrene. Also an ash pans was place, that will mostly be blocked by air tanks later, space with .010 pieces making sure they did not rub on the drivers.
The running boards were made from .040 starting with the section glued to the steam delivery pipes on the cylinders, then the main running board. The main running boards step in at the third driver with rounded corners. They are glued to the side of the firebox, and I used a small .010 scrap piece as a brace to the boiler on the front of the running board.
While the running boards were setting I started work on the pilot, using a dremel to cut the old one off to the coupler pocket.
The new pilot beam was glued to the couple pocket sides and the extra space filled with scrap styrene.
Making a foot board pilot is really just the vertical frame with the boards attached. I build it right on the pilot starting witht he vertical frame.
The cab on these engines sit on top of the fire box ending at the back head, so tho
Shifting focus to the tender, I started with salvaging the original pickups and fitting them to Bachmann trucks. The bearing pocket needs to be drilled out a little to fit the metal one, and the pickups fit best up side down from the way they were positioned on the original arch bar trucks. The old clip mount of the bachmann trucks gets cut off and a hole is drilled for a mounting screw in the center. The wires run through holes conveniently in the original molding of the truck.
The tender frame is made of .040 styrene starting with main flat plate, then the end beams are added. The side bars running the length and the center spine are then fit to inside the space of the end beams. The spine is made up of 3 layers with 2 additional layers as pads for the trucks. Holes are drilled on both sides of the main spine for the wires.
The shells starts with the main tank , gluing the back and sides together. On this one before the front opening pieces went in a gave the box some stability by adding the rear top plate in first. Then the front pieces went on followed by the top front pieces. Two .040 strips were added to the inside corners as filler for sanding the corners round. This allows a broader curve with out jeopardizing the structure.
The rest of the coal bunker was then filled out which does not have to be shaped like this since with will realistically be covered in coal when done. The gangway height is set by having the shell on the frame and marking the height a little lower then the cab floor of the engine so make room for a foot plate.
I have done tender shells with thin styrene but I have found I prefer using the thicker material. Using thinner .010, a under frame is needed for something to build on and to maintain the shape, .040 will hold it’s shape and if the pieces are cut square the shell will be square as well.