This review is on Grandt Line's HO scale GE 25-Ton Critter kit, which is also available in narrow gauge.
Of all the powered non-brass models in HO scale, this has to be one of the smallest of all. Measuring at only 2 1/4" long, it's less than half the size of most two-truck switchers in HO, and is much better scaled than many other 4-wheeled critters in HO scale (especially the old ones still offered by Model Power). The detail is very accurate and finely-scaled, and matches prototype photos very well. The major plastic parts are finely molded, and fit together almost seamlessly (except for the hood, which needed some extra sanding on top). The handrails, lift-bars, and grab irons, which make up most of the detail, are close to a scale 1" in thickness, rather than the 1.75" scale detail in most kits. The cab has a fully detailed interior, and an engineer (or DCC decoder) can be fit inside. That pretty much covers the details.
The kit is made almost entirely from plastic, and the only metal is in the motor, wheels, and detail wire. Most of the parts are quality styrene, but the mechanical parts and finer details are more durable acetal. Most of the kit can be put together with liquid plastic cement, but super-glue should be used for the acetal parts. The parts have little flash, and clean up very easily. The only part that gave me trouble was the right-side window frame, which was destroyed beyond use in the end. The part represents the sliding windows in their closed position, so leaving it off for an open window is still realistic. Grandt Line gives very good instructions, and assembly goes very smoothly as long as they're followed. The most tedious part of assembly was cutting and gluing the clear plastic windows, which is trial and error. A very good size sheet of material is provided, so there's plenty of room for error. Kadee #711 couplers (#714 for narrow gauge) are required to finish the kit, as they hold the pilots in place. No weights are provided, but they are needed, so it's up to the owner to think of something. I made two lead blocks measuring 20.5x8x4mm and glued them in place behind the pilots. The blocks cover the body and coupler screws, so I had to do this part last.
When properly built and tuned, the Grandt Line mechanism is a very smooth runner with excellent control. However, one of the wheels was off-center and caused considerable wobble. The wheel was on the non-geared side, so it was easily replaced with a spare Intermountain 33" insulated wheel (axle is 1/16"). The geared axle is fixed in place, and the front axle is self-adjusting for uneven track. The gear ratio is extremely high (I believe 80:1), so the Critter runs very slowly. At a full 12 volts, the scale speed was only 21.5 MPH, and the Mabuchi motor really whines! I was able to sustain a low speed of only 1 MPH at less than 2V. Not bad at all! Current draw is extremely low, using less than 50mA at full speed (below my power-pack's ammeter range!), and the stall current is around 0.6A. As long as everything's adjusted, a stall should never happen. As I said before, weight is needed for this kit. Without it, I could only make it pull one free-rolling car. With the additional weight, I can make it pull five small free-rolling cars and a bobber caboose on level track. The wheelbase is short, so powered switches or a permanently coupled second unit are needed for smooth switching operation. The stock motor fills the entire hood, so DCC and any other electronics can only be fit in the cab. The headlight housings will fit 1.5mm bulbs.
The 25-Ton Critter is a fun little kit to build, and makes a nicely detailed scale model. Although the basic kit is fairly easy to assemble, I would rate the difficulty at intermediate because of some of the extra work required. But at a retail of only $50, this thing's a really good deal!
