As a child I was fascinated by “dirt scrapers”, as these machines were known locally. They reminded me of dinosaurs. The biggest machines on the construction site, they gorged on huge quantities of dirt, black smoke loudly erupting skyward, and could really move when not scrapping – heady stuff for kids to watch.
The early 1960s was a time of many model companies and hobby alliances. Founded in Austria in 1960 Roco
started the beloved 1/87 HO scale models Minitanks
series of military vehicles: (click here for Minitank Reviews)
. With the success of Minitanks Roco branched into model railroading in several scales. In North and South American Roco was distributed by the late great AHM
: (click here for AHM Reviews)
. AHM, or Associated Hobby Manufacturers, was a multi-faceted hobby powerhouse c.1960s-80s. Modelers of that era, especially model railroaders, no doubt had some of AHM’s products. AHM, until recently, was reincarnated as IHC
, INTERNATIONAL HOBBY CORPORATION, until IHC's demise in 2010.
Sometime in the mid-60s Roco associated with AHM, which distributed Umex Minimovers
(A list of Minimovers are at the bottom of this review). Roco took some Minimovers into their fold. The Roco models are:
1403 - Caterpillar 16 grader
1404 - Caterpillar 631A scraper
1405 - Caterpillar 630A tractor plus 482C scraper
According to our friends at 1/87thscale.info
Roco was founded in 1960 by Mr. and Mrs. Roessler after Mr. Roessler recognized that plastic injection moulding (which was quite a new development then) made it possible to manufacture models with greater detail compared to the metal models that were produced at the time. Initially Roco made Minitank models only, but entered the model railroading market a few years later with HO- and O-scale models. Models in N-scale models followed in 1965.
In 2002 the company, which was privately held, was sold and extensive investments and modernization measures turned Roco into one of the most modern manufacturing plants in the model railway industry. Unfortunately, the investments also led to high indebtedness which ultimately resulted in a bankruptcy in the early summer of 2005.
In July 2005 the Roco assets and trade name were bought by Modelleisenbahn GmbH, this new company will continue production of the Roco models. 
Caterpillar 630A and Scraper
Caterpillar is huge construction machinery company dating back to 1925. “Cat” vehicles in their signature Caterpillar Yellow
are found all over the world.
Although the Cat 630A was a significant improvement on its predecessor, it didn’t have hydraulic controls and was soon surpassed by the 630B.
In order to remain competitive in the rapidly evolving motor scraper marker, early in 1959, Caterpillar began a fairly radical redesign of their popular DW20 series G tractor scraper.
The end product was the model 630A, introduced in 1960, second in the 600 series of Cat motor scrapers (the first was the 619). Closely resembling its predecessor externally, the 630A was in fact quite a step forward for conservative Caterpillar in a number of areas.
Replacing the former DW20’s Cat D337 diesel was the new model D343T, a six-cylinder, in-line, turbocharged and after-cooled diesel, featuring twin overhead camshafts. The D343T was rated at 335 flywheel horsepower and was connected to an all new Caterpillar nine-speed barrel type powershift transmission with a torque divider for maximum use of available power.
Another innovation was the use of planetary final drives, a first for Caterpillar on a three-axle scraper.
A considerable amount of attention was paid to the styling of the tractor unit. Gone was the angular somewhat austere look of the DW20, replaced by more flowing, rounded lines and a nicely sculpted bonnet and radiator guard.
Two kinds of lowbowl scraper were offered for use with the 630A – initially the 27 cubic yard, struck 35 cubic yard heaped No.482 series C, and soon after the model 630A rated at 21 cubic yards struck and 28 cubic yards heaped.
Both the No.428C and 630A scrapers featured an air operated cable saver device to prevent double-blocking and subsequent cable breakage.
Despite the outdated scraper, the 630A was well accepted by the contracting community and sold well for the reasonably short time the machine was in production.
A number of ancillary manufacturers offered optional trailing units for use with the 630A tractor, most notably Athey who produced rear dump, bottom dump and side dump wagons in their PR range of equipment.
The Hyster company, better known for its forklifts and logging winches, manufactured a double drum sheepsfoot roller for use with the 630A tractor.
It would appear in hindsight that Caterpillar could see the writing on the wall in regard to hydraulics and scraper operation as the 630A was only in production from 1960 through to 1962 when it was replaced by the 630B – a machine with all hydraulic functions. 
Roco Caterpillar 630A Tractor plus 482C Scraper
The model is packed in a Roco carton with a cellophane window. It is molded with shiny yellow plastic with black plastic tires. "Umex" is still molded on the bottom of the scraper. Caterpillar painted their company name in black; this is replicated on the scraper but not on the tractor.
Molding is sharp with minor flaws, a few slight sink marks and light flash. The model has good detail. The CAT diesel has basic simplified detail that is better than the other Umex models previously reviewed here. The driver seat is still way too small. The model lacks all the cable and tubing from the tractor part to the scraper pan. The headlights are neither clear plastic nor simulated with paint. Enjoy the photos of the model.
The machine is authentically articulated, the scraper raises and lowers, and the front of the pan opens and closes.
I have not found many of these models on on-line auctions. This Umex Minimovers/Roco scraper is a good model. Reasonably detailed, the model is fairly in scale. It’s an imposing machine! It will look good on any model railroad or construction diorama. Recommended.
• U301 Caterpillar 4-wheel tractor
• U302 Caterpillar 4-wheel tractor
• U302 Caterpillar Traxcavator
• U303 Caterpillar 16 grader
• U304 Universal backhoe crawler
• U305 Caterpillar D8 bulldozer
• U306 Hamm road roller
• U307 Universal crane truck
• U308 Caterpillar 631A scraper
• U309 Euclid R45 dumptruck
• U310 Construction crane
• U311 Hamm tandem roadroller
• U312 Universal clamshell crawler
• U313 Caterpillar grader
• U314 Caterpillar 4-wheel scraper (for U301)
. Richard Campbell. The Caterpillar 630A
. Contrafed Publishing Co. Ltd. Contractor Vol.32 No.1. February 2008. http://www.contrafedpublishing.co.nz/Historical/Classic Motorscrapers/The Caterillar 630A.html.