Hey, everyone. I just got what could be a great idea. For small steamers, getting a good motor inside narrow boilers is often times impossible, and driveshafts between the engine and tender are far from prototypical, so how about this: maybe the bachmann 70-tonner mechanism can be used with a tender shell, new truck sideframes, and with the fuel tanks removed to make a great-running tender drive for steamers! Maybe I can try this for a small SD&AE branchline steamer, one that I otherwise couldn't build...
I like it! I have found that several cheaper steamers will roll pretty freely if you take out all the loco's gearing, usually the side mechanisms are pretty low friction. Bet you could fir it in a Bachmann USRA Long tender!
This is the expiriment I did just by placing a Kato 2-8-2 tender over top of the Bachmann 44-tonner mech that I'd modified for my 70-tonner. This was a while back. It's a little high, so some tinkering will be necessary....but yeah, maybe. But after expirimenting, I wouldn't do it again. A locomotive has too much drag and you can't get enough additional weight in the tender. I went back to tender drive for my little 2-6-0, really heavy cast boiler, 8-wheel Kato pickup on the tender, and tightened up the cab-tender dimensions to prototypical dimensions. The weight of the motor in the tender gets you the solid pickup you need, the cast weight in the boiler makes it way heavier than a motor could get. Win-win. I do think this has promise for something big enough to use a tender this size though; at least a 2-8-0; DCC could independently control the boiler and tender motors for speed matching. If you need a really small, high-torque, low-speed motor to fit in a boiler, look at some of the Gizmoszone gearhead motors. With DCC, just drop the voltage down to the 3v max, with DC use a 100-ohm resistor. I'm using those in my Climax A's.
this is the concept I am going to use for another Loco project. Alot of European prototype, Especally Fleischmann. I have one of their Heavy Pacifics for the DB, ant it runs pretty well, the locomotive is so Precisely machined and assembles, it will roll by it's self, Sams Tender, down a 1-2% grade. The flaw it does have, is the pick up, this is a older loco, and it only has pickup from the drivers, though whipers that contact on the top of the drivers flanges. For this idea to actually work, you need a solid, powerfull drive, a super smooth locomotive, and most inportant, ALL WHEEL ELECTRICAL PICK UP!!! Although, I am looking a possible re-design, using tender motor, and looc drive like the Athearns 2-6-0/2-8-0 or Bachmann 4-4-0, overall I think this is a better design.
IHC did something similar in HO with an 1880s 2-8-0. They put the tender onto what is essentially a diseasel chassis and had it push the locomotive around. I once saw one pull something like twenty five HO scale boxcars up a three per cent grade at twenty SMPH. I doubt that the prototype could have done that. Given the small size of the locomotives that would benefit most from this, it would probably be necessary to pack it with weight and have one of the tender trucks have all four wheels with traction tyres. This would necessitate that at least all of the drivers on the locomotive be live. Having the idler wheels live, as well, would be even better. The other thing required would be better than mediocre trackwork, as the forces and stresses on a pushed locomotive are different from normally configured model locomotives. I am building a pike that represents a non historic railroad that operates small power and is set in the 1950s, so it does not require the el-huge-o rolling stock, either. This allows me to use nine and three quarter curves and #4 turnouts, but due to the cramped space, I am committing several trackwork NO-NOs such as turnouts close to curves, using the diverging route on a main line and I have run into problems, but with the SECTIONAL track and PECO turnouts (and going through them in the trailing direction more than the facing, mind you). The flex track sections have caused no problems. I am having more problems with the freight rolling stock and power than the passenger. I am using MP eight wheelers and MDC moguls for passenger power and B-mann Standard shorty cars and MDC fifty and thirty four foot cars and they cause few problems. The only problem that I can not seem to correct is that the mating of a truck mount coupler on the MDC 2-6-0 with a body mount in the MDC fifty foot passenger car causes the leading tender truck to derail on a nine and three quarter curve. If I use the MDC 2-8-0 with a body mount and the MDC fifty foot car with a body mount, there are no problems (figure out THAT one). The passenger trains run at about forty SMPH. The freight power is Kato SW, LL SW, LL BL-2, Atlas RS-1, Atlas Baldwin B-mann 44 and 70 tonners. Locomotives and freight cars are derailing here and there on sectional track and PECO turnouts. The freight trains run at fifteen to twenty five SMPH. I have always been able to find the gremlin and correct it, but I have never had so much trouble with sectional track. I have never built a pike of this size that favours operating over running with such tight constraints and I am learning why the experts discommend certain practices. It also became more clear to me that it was with good reason that I have always operated a pike before adding the ballast and glue. I have had to make many corrections to this one and I expect to make a few more. It is not that difficult to make the corrections now, it is simply a matter of pulling up a few nails and changing out sections of track or correcting deformities. What amazes me is that I am not having problems with the flex track sections, it is with Atlas sectional and PECO turnouts, and those are two high quality manufacturers. I suspect that the locomotives that would benefit most from this would be those used on smaller pikes. If the manufacturers of US prototype locomotives were to go with this, we would need to brush up our trackwork skills. Still, a good idea. I suspect that we would get better pulling power out of eight wheelers, moguls and switchers if the manufacturers did this.
The Kato Pocket Line Steam locomotive uses a powered coach to push it around. It could be used as a extremely short line or amusement park train.
This started out as a Micro Ace 4-6-2. After I shortened it, the motor hung way too far out the back of the cab so I moved it to the tender with a drive shaft made of RC airplane fuel line. I packed the boiler with tungsten in every nook and cranny. The little guy can now pull the track up behind it.
The tender drive concept has been used successfully for quite a while by Minitrix and Fleischmann, and probably otheres. Minitrix boilers are usually metal with very low friction running gear. Tenders usually have all axle pick up. Works well. Still sounds like a diesel running to me, though. Dave
Aren't the very successful MDC/Athearn 2-6-0 and 2-8-0 locos tender drive? Those locos are awesome - terrific runners right out of the box! I've always wanted someone to copy the concept, but it seems the purists don't like the (almost invisible) drive shaft...
Those locomotives have tender motors, but they drive the engine's wheels via a driveshaft. The definition of "tender drive" that I'm familiar with is having a motor in the tender drive the tender wheels, using something like a diesel chassis...but I may be wrong... ...and yes, those engines are amazing. I've had one at some point (kitbashed it, then re-kitbashed it, then re-re-kitbashed it again and somehow it got ruined). However, my SD&AE roster only has room for one: SD&AE's little 2-8-0 #50, which was actually demoted to yard switching because it was so small (under 70 tons!)
