Thanks for posting your experience with this loco! I have thought about buying one and doing similar and your post has answered many questions I've had.
Cheers!
Dana
Two seasons in my Canada, Modelling and Paintball.
One thing I like about this locomotive is that it's built like the prototype in terms of the way it articulates. The rear engine is rigidly affixed to the locomotive frame while only the front engine, connected to the rear engine by a link, is free to swing while negotiating curves. Some model articulateds are designed to have both engines pivot and/or swing in order to accommodate sharp curves. With its 50" diameter drivers, and relatively short rigid wheelbase, negotiating sharp curves as befits a logging railroad should not be a problem for this engine.
In order for the front engine to support its share of the locomotive weight and to ensure good tracking and current pickup, a spring-loaded pin projects upward from it and contacts the bearing plate attached to the underside of the boiler. This applies a downward force to the front engine while allowing it to follow curves and accommodate changes in grade.
Finally, both the front and rear pilot trucks are spring loaded with Mantua's conical spring to help keep their wheels on the rails and aid in tracking. While testing the locomotive for its current pickup paths, I discovered that the metal front engine housing is electrically live. Thus, if a metal leading truck with an uninsulated wheel on the engineer's side were substituted for the factory part, it would provide another current pickup point - 4 wheels instead of 3.
Although the OEM lead and trailing trucks are slightly different (2-different model numbers), they share the same characteristic of being an outside bearing design and, being made of plastic with double insulated wheels, they were never intended to act as a current pickup. Now, every photo I've seen of the Baldwin standard gauge articulated loggers show them as having inside bearing lead and trailing trucks usually with spoked wheels. As luck would have it, I happened to have in my junk box a brass, 2-wheel, inside bearing truck with a single-insulated wheel set (although solid nickel silver, not spoked) with the axle center to mounting hole distance being close enough to the factory truck to be usable as is. I did have to turn the wheel set to place the uninsulated wheel on the correct side but this was easily accomplished as it is held in place by a screw-mounted retainer plate. I also had to drill out the mounting hole in the truck large enough to just pass over the mounting boss in the front engine where it is retained by the factory screw. Additionally, I was able to use Mantua's conical spring to maintain pressure on the lead truck to enhance both tracking and current pickup. There is a hole just in front of the lead truck mounting boss into which the smaller end of the conical spring fits thus helping to maintain it in position. If the front engine is allowed to swing to its most extreme point, either side, the spring will fall out but once on the rails this can't happen and the spring will remain securely in place. Just be careful when carrying it around. I finished up by painting the truck with PolyScale steam power black which is a good match to the factory finish although the lead truck frame can barely be seen in its mounted position. I was careful to keep the mounting point and the area where the spring contacts the truck arm free of paint to ensure good electrical contact.
I now have a lead truck that is both functional and much closer to prototype in appearance. I could perhaps obtain a spoked wheel set for even more realism but obviously the first priority is to change the trailing truck to a similar type as it does look a bit odd in its present configuration, as you might expect. However, the rear engine is not electrically live, as I discovered in my prior testing, so the trailing truck could not be used for electrical pickup in the same manner as the lead truck, and any change would only be cosmetic. A number of companies make brass pilot trucks, some of which could be suitable, but even a plastic one would do as long as it was an inside frame type. Of course, both front and rear pilot wheels should be the same diameter.
Well, did it make a difference? After testing the locomotive with both the factory lead truck and my own live version, I can't honestly say that it did. Over the long run however, as the track and wheels accumulate dirt in the normal course of events, having an extra wheel picking up current might be helpful. Only time will tell but it certainly can't hurt.
For better or worse, so ends my tale.
I've always liked Baldwin's Articulated Loggers and although not my principle modeling interest I do have a logging line as an adjunct to my main layout, providing me with all the excuse I needed to acquire one. I understand that the model is a scaled-up version of the Uintah narrow gauge machine and thus no prototype exists for the mantua model. Nevertheless, it's close enough to suit me and of course it can be super detailed to more closely resemble a prototype Baldwin. Although there are some brass beauties around based on the Baldwin prototypes, they are way to rich for my blood, and I'm very happy with my choice.
I purchased my model from Trainworld and I selected #353001, a black-painted, undec, DCC ready, saddle tank, oil-burner version because that's closer to the Baldwin prototypes in the photos I've seen than the side tank versions. I always buy DCC ready where possible because I prefer to install my own decoders and I don't like sound.
The reason for this post is that I've read a number of articles stating that these models have current pickup problems along with different ideas of just how many wheels are involved in collecting current, one poster even maintaining that because the right rear driver of the rear engine contains a traction tire, this assembly only has 2-wheel pickup. I wanted to find out for myself just how Mantua accomplishes this feat.
The first thing I did after receiving the locomotive was to run it on my layout with the throttle set to 0000. It seemed to run okay so next I replaced the couplers with scale-head Kadees. The loco came through from the factory with a pronounced droop in the front coupler so I corrected that problem as well.
Installing a decoder requires that the oil bunker be removed by pulling it straight back then pulling the cab up and back. No screws are involved but be careful pulling so as not to break anything. Once removed, a rat's nest of wires awaits you which terminates in a 9-pin socket connected to a dummy plug which allows the engine to run in DC. Remove the plug and plug in the decoder of your choice. Since I have the Lenz system, I used a Lenz Gold JST-MP decoder which plugged right in to the OEM 9-pin socket. I placed a piece of thin double-sided tape on the side of the decoder which faces forward against the metal motor mount to prevent a short that would destroy the decoder. The rear facing side of the decoder needs no protection since it's surrounded by the plastic oil bunker. The decoder fits in the limited space nicely and I give the factory credit for their ability to pack a sound decoder in that confined space along with a speaker. Placing it back on the rails with the throttle set to 0003, the engine ran smoothly even without being broken-in.
Now I turned to investigating the current pickup. I placed the engine on an unpowered section of track and used my DVM set to ohms to trace the current flow. The three wheels on the right (engineer's side) of the front engine pick up current. There is a terminal atop the front engine housing to which a red wire is attached that carries the current from that rail to the decoder input. The DVM reading from each of the three wheels to the terminal is ~ .1 ohm, the resistance of the test leads. The three wheels on the left (fireman's side) of the front engine are insulated. In like manner, the three wheels on the left (fireman's side) of the rear engine pick up current while the three wheels on the right side (engineer's side) of the rear engine are insulated. Since only the right rear wheel on the rear engine has a traction tire, it in no way interferes with current pickup.
So, 6-wheel current pickup with three on each rail. I didn't have current pickup problems during my subsequent testing on my layout so I concluded that the factory system was adequate in this regard. However, there is an easy way to improve on this by enabling the front pilot truck to also act as a current collector for those who feel more is needed. I will explain in my next post.