Introduced: 1973 (Kato version), reintroduced in 1997 (as part of Con-Cor's "Rail Baron" collection)
This locomotive was originally manufactured for Con-Cor by Kato (Japan), a relationship that lasted until 1989 when Con-Cor and Kato parted ways. As part of the split, all of the tooling for Con-Cor branded models was returned from Japan to the USA. Starting in 1997, Con-Cor starting producing "in-house" versions of this model for sale under their new "Rail Baron Collection" label (and with most of the actual manufacturing taking place in China). Kato used their same U50 mechanism for the Con-Cor/Kato Gas Turbine model (introduced in 1975).
These are nice looking models and decent enough performers. The mechanism is a variation on the horizontally split-frame design used in the Con-Cor/Kato Alco PA model of the 1960s. The motor is an open-sided 5-poler. Most (if not all) of the gearing is plastic. Only the outer two trucks provide pickup and propulsion. All 8 wheels on said trucks are geared and provide pickup (there are no traction tires). All current is transferred to the motor via the metal chassis itself, so there are no wires (apart from the ones for the headlight). Said headlight is directional and mounted on the cab end of the chassis (and unfortunately, it lights up the entire cab from within). These models have reasonably low-profile wheelsets and have no problems operating on Code-55 track. The Rapido-style couplers are truck-mounted (although the truck-mounting is actually prototypical in this instance).
Like the Kato PA, these models run smoothly and reasonably quietly (although a bit louder than more modern models). Pickup is good, slow speed creep is exceptional, although the top-end speed is off the charts. Given the heft of the huge metal chassis, pulling power is excellent. The main issue I've encountered with these models is with the middle trucks, which tend to be a bit problematic. They don't provide any pick-up or propulsion, and being very light and basically free-floating (IE, not attached to the chassis) about the only thing they're "good" for is occasionally derailing.
The differences between the Kato U50's and the later Rail Baron U50's are minimal. First and foremost, the motor was upgraded from a standard 5-poler to a 5-pole skew-wound job. And the newer motor does provide for a slightly smoother and quieter ride, not to mention a much lower top-end speed. About the only other noteworthy change that I can detect between the two is blackened wheels on the Rail Baron version. Apart from some minor paint differences, the shells themselves appear to be identical. For example, the handrails on my Kato UP unit are gray, whereas they are yellow on my Rail Baron UP U50. Which version is actually correct is, I guess, up to the UP experts to sort out.
Early versions of the Kato-made models used wheelback wipers to conduct current from the wheels to the metal truck halves. Said wipers were prone to collecting a lot of dirt and needed to be cleaned fairly regularly. These wipers were dropped fairly early on by Kato, with the trucks being redesigned such that current flowed from the axles directly into the truck halves.
Some of the early Rail Baron runs appear to have been put together using at least some parts manufactured in Japan (old stock leftover from before the big break-up, I guess). For example, it's quite common to find "Japan" stamped on the bottom of the fuel tank on some of these first runs. The molding was eventually changed and new fuel tanks (along with presumably everything else) were manufactured in China. Models from these later runs will be stamped "China" on the fuel tank.
Note that only the Union Pacific and Southern Pacific versions are even remotely prototypical. All the rest of Con-Cor's paint schemes are (as was there wont) complete fantasies. EG -
These models were discontinued circa 2005 as part of Con-Cor's "The Boss Is Retiring" downsizing effort. New DCC-Ready versions were announced at one point (scheduled for delivery in 2013), but at this point in history it seems unlikely that that project will ever come to fruition.
Collector note- the box that I got my Kato U50 in looks exactly like a contemporary Kato box (including the inserts) and makes no mention of Con-Cor. What I've been told is that Hobby Center Kato sold all of the Sekisui Kinzoku (IE, Kato) production in their shops in Tokyo and Osaka in Kato boxes (regardless of the US label). Hence, one might have found Con-Cor, Atlas, and Stewart US profile locomotives in Kato boxes with no mention of those brands. The most notable example of this "gray market" is the batch of Atlas GP7s and GP9s that made it into the USA via a distributor which were in standard Kato packaging.
Reviewed: 9/75 Railroad Model Craftsman, 1/74 Railroad Modeller, 1/74 Model Railroader: ("The Con-Cor N scale model is an accurate reproduction of the GE behemoths. The body is a highly detailed plastic casting with most details cast on. The cab windows are clear plastic and the headlight and number boards are illuminated by a 12-volt lamp with a diode for directional control... The frame is an ingenious sandwhich of plastic insulating parts and zinc-alloy castings which position and secure the five-pole motor, gears and transmission. Most of the gears are plastic. Two of the four trucks are powered; the other two are idlers. The scale 48"-diameter wheels are nickle silver. (The prototype has 40"-diameter wheels.) The flanges are .030" deep and the check gauge is .31" (7.9 mm). The Rapido-type automatic couplers are truck-mounted. For once, this is prototype practice, since the U50 has span bolsters and the couplers are attached to these and swing with them... Our sample ran smoothly at all speeds. The maximum speed is very high; yet the model can be controlled to provide smooth performance at scale speeds. The minimum speed is very good as N scale models go. Few others are capable of running this slowly... This is a fine locomotive for heavy-duty mainline operations. Price: $49.95")