Back in the November 2005 issue of Contractor we had brief look at the M.R.S Company (Mississippi Road Supply) of Flora, Mississippi, USA.
I didn’t have a great deal of column space in those days so I have chosen to do a more in-depth feature on this little known manufacturer.
The Mississippi Road Supply Company was established in 1943, originally in Jackson, Mississippi, and following WW2, a shift being made to larger premises in Flora, Mississippi on the site of an ex-Army ammunition manufacturing & storage depot.
M.R.S. manufactured 4-wheel drive towing vehicles for all four branches of the US armed services (Army, Navy, Air Force & Marines).
These machines were often equipped with towed scrapers or bulldozer blades and were found to be very versatile and rugged in operation.
During the war years most of the attachments for these macines were supplied by Bucyrus-Erie.
Following WW2, many of these machines were sold as army surplus and found their way into civilian hands where they were used in construction and agriculture.
M.R.S. did not rest on its laurels and began to develop further different types of tractor units.
As Bucyrus-Erie was by now a prime supplier of equipment to International Harvester, supply of ancillary equipment could not be guaranteed so M.R.S. formed an alliance with the Wooldridge Manufacturing Co., of California.
This arrangement, which was beneficial to both parties, lasted until 1958 and was responsible for the development of some of the largest single open bowl scrapers ever built.
M.R.S. tractors were primarily ‘assembled’ machines.
By this I mean that while M.R.S. built the chassis and some primary systems, all of the other necessary components were supplied by outside manufacturers (similar to the way that Peterbilt or Kenworth build a truck).
Customers could specify their choice of powerplant, transmission, axles etc., and M.R.S would set to and turn out the finished product.
Wooldridge supplied the scraper and in some instances the controls to operate it as well.
M.R.S. only ever manufactured 4-wheel prime movers and one of the most unique features was its 4-wheel drive and steering systems which allowed the machines to traverse all manner of hostile landscapes without becoming bogged.
Even ‘crab steering’ was possible, if necessary, to get around obstacles.
The all wheel drive nature also gave the machines tremendous useable traction for self loading.
Other features incorporated into M.R.S. tractors included a front push plate or blade and a traction aid control on the earlier, larger model 200 & 250 tractor units which transferred weight, via a large single acting hydraulic cylinder, from the scraper to the tractors rear drive axle.
M.R.S.’s primary customer was always the US military.
Although it also manufactured for the domestic US construction market as well , this seems to have been fairly localized as the big money always remained with Government contracts.
Competition for this market also came from Clark, FWD-Wagner and Caterpillar who all developed machines to vie for a slice of the Government pie.
Clark had the 290M, FWD-Wagner the WT-14M and Caterpillar a variant of the 834 wheel dozer known as the 830M (the M in all cases standing for ‘Military’).
Following the acquisition of Wooldridge by Curtiss-Wright in 1958, M.R.S. were suddenly left without an equipment supplier, spurring a hasty trip to the drawing boards and a passing acquaintance with Euclid.
As a result, from the early 1960s onwards, the majority of M.R.S. open bowl scrapers were of its own design.
In a bid to broaden their product range, M.R.S. also formed an alliance with Hancock to produce elevating scrapers for them.
This turned out to be a very successful move as from around 1967 the majority of M.R.S. machines were sold in this configuration, M.R.S. eventually even producing its own elevating scraper units.
Common Types
As mentioned previously, M.R.S. tractor scrapers were manufactured in both conventional and elevating configurations.
The following lists the most commonly produced models:
Conventional: I-25 (8 cubic yards); I-95 (18 cubic yards); I-105 (24 cubic yards); I-110 (32 cubic yards); 200 (35 cubic yards) 250 (48+ cubic yards)
Elevating: I-80 (12 cubic yards); I-90 (14 cubic yards) I-100ES (18 cubic yards); I-110ES (32 cubic yards)
These were powered by a variety of engine/transmission combinations including International, Cummins & GM diesels with Allison, Spicer, Twin-Disc or Fuller gearboxes.
Service
Militarily, M.R.S. machines were used worldwide, and especially so in Vietnam where they saw extensive service.
As is the case when the military is finished with an item, many subsequently found their way into civilian hands via Government disposal auctions, changing hands for less than their scrap value!
Epilogue
M.R.S. finally went out of business in the late 1970s.
The very nature of the way the machines were manufactured and their limited production runs meant that they were uneconomical to produce for the commercial market.
However, due to their simplicity and extremely rugged design, many M.R.S. machines still soldier on in the USA today.
Despite the ‘kitset’ nature of the machines which made them expensive to produce, it also guaranteed them a long life as components are still readily available from all those folks that originally supplied M.R.S.!
Taylor Machine Works purchased all the assets of M.R.S. in the mid 1980s and although not manufacturing per se, will custom build one for you if required.
The New Zealand Connection
One M.R.S., a model I-110, was imported into New Zealand by Lion Machinery of Rotorua minus it’s scraper and converted into a self propelled compactor.
Owned by Barry Andrews Earthmovers of Rotorua, its first Antipodean job was on the Police training college site at Porirua in 1975.
It was last seen rusting away on a used machinery lot in Rotorua, gutted of its GM 12V-71 engine.
For The Diecast Model Collector
Surprisingly, considering the rather low profile of M.R.S., there is a limited edition model available of one of it’s machines.
This is a mixed media (resin/white metal) 1:50th scale model produced by EMD Models in Eastern Europe and represents a mid-1950s M.R.S. I-250 tractor towing a 50 cubic yard Wooldridge OS-50 scraper.
Quite an investment at over US$550, it is none the less a very impressive model of a very rare subject.