I am trying to scratchbuild a steam locomotive, but I keep starting over because I am inexperienced and a perfectionist, which may be a bad combination. I feel like the logical place to start for a build is the frame. I am debating between a simple block style frame like on model trains or going all out and doing a cast open style frame like real locomotives. Does anybody know if suspension has been made for an HO model? Are functioning leaf springs even possible?
Continuous springy beams are the latest thing... Guitar strings are used. http://www.clag.org.uk/beam-annex3.html#CSBs-inside-wheelbase
You might try looking into the British 4 MM Society as they have a lot of fanatics building complete suspensions for 4 MM scale models (close to HO 3.5 mm scale) in brass or nickle silver. North American suspension practices for steam locomotive suspensions are a little different than British as their frames are usually steel plate rather than bar or cast. The techniques they have are what you need to focus on. Just don't call it OO scale as that is a uniquely UK compromise of 4 MM scale running on 16.5 MM HO scale track used by 95% of British Outline railroad hobbyists but anathema to the 4 MM purists.
Why on earth would you scratch build something as complex as a steam loco; frame/cab, boiler/domes/ piping and other details/rods,cylinder action/wheels, quartering, axles/pilot, pilot truck, pony truck /cab,tender/lighting/motor-install, electronics, et al, with NO experience ?! I'd first see how well I could build, say, a caboose or diesel shell. I mean, why go through all that not knowing you'll be successful or not; whether you'll even be able to complete the whole difficult process ?...Leave alone all the ready to run excellent commercial stuff available. I mean, I do wish you luck with it. But it sounds too enormous a project, considering your stated inexperience...M, Los Angeles
No, the axles don't contact the leaf springs. U.S. steam locomotives universally utilized 'walking beams'. The simplest version of this was used on 4-4-0 types from the late 1930s, and also many, many tandem axle trucks; the truck version was most famously made by Hendrickson. Two axles are mounted to each end of a stout steel beam, and that beam is mounted to the leaf spring which is connected to the frame. There is one walking beam per side, and each holds that end of two axles. This keeps the weight borne by each axle pretty well equalized, even on wavy rail. When one wheel hits a bump, instead of transmitting the full shock to the frame, leverage cuts that shock. If one wheel rises and the other dips due to imperfect rail, hardly any shock is transmitted. The walking beam tilts, but the center of the beam rotates instead of compressing the spring. Where more than two drive axles are used, a system of interconnected equalizers is employed. So, the ends of the semi-elliptic springs are in contact with the frame, and the centers are in contact with the 'walking beam' equalizers. Only the equalizers are connected to the axles.
