Introduced: 1972, revised 1975, 1983 and 2004 (all dates approximate)
Like the rest of Bachmann's line of iffy trainset locomotives, their venerable 4-8-4 has a long and tortured history of revisions and modifications. There have been four basic mechanisms employed in this model (that I know of), although the locomotive and tender shells have remained the same throughout.
The initial 1972 release came packaged in a yellow cardboard box (with the locomotive and tender in individual black/yellow plastic clamshells inside said box). All pickup is derived from the 8 drivers (transferred to the chassis via really clunky looking wheel wipers). The headlight is housed inside of a weight inside the smokebox. The motor is a square, open-sided 3-poler. All of the running gear is blue (huh?) plastic. The "long distance" tender has a Rapido coupler on the back and the locomotive has a small dummy knuckle coupler on the pilot. The tender hooks to a plastic drawbar on the locomotive. No traction tires.
Performance on this first version isn't great, although I've certainly seen worse. Throttle response is actually quite fine, as is slow speed creepability. On the downside, it's loud enough to wake the dead. Worse still, the limited pick-up scheme makes navigating through turnouts without stalling a virtual impossibility. On the plus side, it doesn't seem to have any problems holding the rails on sharp (9.75"-radius) curves. Pulling power seems adequate.
To remove the locomotive shell, unscrew the screw in the boiler dome (in the middle of the shell) as well as the screw underneath the pilot truck. The shell should just slide up and off at that point.
The second version (released sometime in the mid-to-late 1970s) has a competely redesigned mechanism. The headlight is now mounted to the chassis (rather than living inside the shell). The pickup scheme is completely redesigned. Left-rail pickup comes from the left four drivers (and no more wheel wipers), while right-rail pickup comes from the tender (from the inner two wheels on each truck). The drawbar has moved to the tender, which hooks onto a peg on the locomotive. Current is transferred from the tender to the locomotive via a stiff wire on the drawbar. The third set of drivers (counting from the front) no longer has flanges (who knows why), while two of the drivers on the right side (front-most and rear-most) now have traction tires. The motor appears to be the same one as on the first version. The running gear is still plastic, albeit now black. The locomotive shell is held to the chassis by a single screw in the smokestack, along with a couple of clips at the back of the cab. The forward truck has a spring added for downward pressure. AFAIK, these came in the same black/yellow packaging as the first version (or at least mine did).
Maybe it's just the one I have, but performance on this version is actually quite a bit worse than on the first version. Moving all the right-rail pickup to the tender seems to me to have been a zero-sum gain. Worse still, the addition of thick traction tires has definitely introduced all kinds of wobbliness into the equation. And the springloaded front truck? Hell, it won't stay on the rails at all! Oh yeah, and it still runs loud enough to wake the dead. And my most hated feature of this version? Trying to keep the damned drawbar between the locomotive and tender coupled while getting all those wheels situated on the rails! All told, this version is definitely the worst of the bunch.
So, along came 1983 and the whole damned thing was redesigned yet again (now housed in the familar Bachmann "big white box"). The motor is a closed "can" job (no idea how many poles, but judging by the meteoric top-end speed, I'm assuming three). The running gear is now metal (although the hangers are still black plastic). The pilot truck spring is gone, as are the non-flanged drivers and the tender pickup. Pickup is now derived from the front six drivers (the rear two having thin traction tires) along with both the pilot and trailing trucks (the pilot picking up one rail and the trailer picking up the other). All wires have been removed from the equation (yay). The drawbar is still connected to the tender, but the locomotive now has a nice oblong hook that helps keep the danged thing reliably coupled. Once again, the locomotive shell is held to the chassis via a single screw inside the smokestack.
Performance on this version is actually quite respectable. It's still a bit loud and toyish sounding, but nowhere near as loud as the earlier versions. Throttle response and slow speed performance are both decent. The motion of the running gear is pretty smooth, pulling power is good, and getting through turnouts and around narrow radius curves doesn't seem to be a problem. If I had to pick one, I'd say this is the best running version of the bunch.
Circa 1989, Bachmann released a Union Pacific Overland edition of this third version- IE, same mechanism and same locomotive shell (albeit with a fancy paint job). The only real difference is the fancy box, the fancy price, and the Vanderbilt tender (cannibalized from Bachmann's 1983 2-8-2 Mikado model).
Circa 2004 yet another completely new 4-8-4 was introduced (this time available with fancier paint schemes and a choice of tenders). This one has a new motor (smaller, rectangular and with closed sides - sorry, can't count the poles for ya). The pickup scheme is the same as in version #3, as is the running gear (although now blackened). The chassis is a slick looking split-frame job. The screw holding the locomotive shell to the chassis has once again moved, this time from the smokestack back to the boiler stack in the middle of the shell. The traction tires have also moved, now located on the third set of drivers (counting from the front). These come packaged in a clear plastic jewell case and are still being manufactured to this day.
I actually bought one of these brand-spanking new, and I have to say, it doesn't quite measure up to version #3. Yes, it runs a bit quieter than #3, and I like the snazzy paint job. Unfortunately, the performance seems to have taken a slight dive. The first thing I had to do on mine was regauge the wheels, all of which were spaced way too widely (locomotive and tender). Next, I had to run it around for a couple of hours just to get all the factory crud off the wheels (blackening - it's a blessing and a curse). And even after all of that, it still ran just a little bit funky. I mean, not horrible, but the locomotive was just herky-jerky enough, and the Vandy tender was just wobbly enough to keep this thing firmly entrenched in "trainset locomotive" territory (IE, no "A" rating here).
Note- Bachmann released a Norfolk & Western 4-8-4 "J Class" steamer in 1988. That model has nothing in common with this one (different shell, different mechanism, etc).
Grades: C (for the first version), D (for the second version) and B (for the last two versions)
Reviewed: 1972 NMRA Bulletin, 5/72 Model Railroader: ("The ready-to-run model, manufactured in Hong Kong, closely follows the scale dimensions of the prototype in most places. The model is well proportioned. The entire superstructure is a one-piece plastic casting with detail cast on. The frame has both plastic and zinc alloy castings. The drivers have plastic centers and metal tires. The valve gear and rods are plastic castings, as are the pilot and trailing truck frames. The pilot truck wheelsets have brass hubs on the axles to provide tracking weight. A three-pole motor drives the worm-and-gear/spur-gear drive... To provide clearance for the bulky valve gear there are no side rods to the front drivers. This is noticeable only under close scrutiny. All wheels are smaller in diameter than those of of the prototype by about scale 5". With the .020"-deep flanges, the overall diameter is close to prototype relationship. The check gauge is .325". The tender shell is cast in plastic. The plastic frame is weighted with sheet metal and a small lead base casting. The truck frames are one-piece plastic castings... Our sample ran smoothly, though it was a bit noisy... The minimum scale speed is high... At full voltage, the model speed approximates the maximum scale speed of the prototype, which often ran at the 100 MPH range. This is very good... A notched cylinder design allows the pilot truck to swivel enough to negotiate short radius curves. These notches and the large valve gear (scale 13'-6" wide) do detract from the model's overall appearance. Price: $30.00")