New Ashford, Massachusetts 01237
An article on fairly modern tractors and equipment, 1950 era,
may seem out of place in an old engine magazine; however, articles
of this type do approximate points on the development curve line
for this type of mechanical power. By projecting this line, taking
in the effects of fuel scarcity, conservation, economic and
environmental conditions, one can envision nuclear and solar
electric powered tractors operated by a computer while owners are
out playing golf or fishing. On the other hand numerous high-priced
studies may discover a renewable fuel and renewable power formerly
known as hayburning horse and mule power, so let us get back to an
old subject: the 200-ton roller or compactor and diesel powered
tractors.
Pneumatic tired rollers of various types and sizes up to 100
tons had been around since before World War II but the 200-ton is a
one-of-a-kind especially built for testing and producing maximum
compaction of the subgrade for the heavy duty runways required by
the then new B52, a military plane weighing 207 tons fully loaded,
and the new line of large cargo and passenger carrying jet planes.
To support planes of this size and value, pre-testing is a must as
one cannot afford a failure under use. So the specifications called
for six passes, one on top of the other, of a 200-ton roller on a
forward and reverse pattern over every square yard of the subgrade.
This is the cut or fill grade that is prepared for the base courses
and pavement. It is based on the old professor’s accolade,
‘A road is only as good as its foundation.’ Therefore, if
the subgrade will support a 200-ton roller now, when gravel and
base courses and 18-24 inches of pavement are added, it will
support 200 plus ton planes in any weather condition. We did pick
up numerous weak areas which had been readily passing a 25-ton
roller. Some areas did not fail until three or four passes were
made. Then the bottom fell out and it was quite a job to pull out a
200-ton roller! Of course, all areas were corrected and
re-tested.
By referring to photo #1, notice the method of assembly to move
the roller from one job to another required three flat cars, one
for each two-wheel half-section and one for the front drawbar, rear
connecting link and pig iron ballast. When assembled empty, it
weighed 125 tons, then 75 tons of ballast equaled the 200 tons.
Space was also available for another 50 tons of ballast, if
needed.
Both Allis Chalmers HD 21s and Caterpillar D8s were used for
hauling. They were the big boys at the time and quite common on
construction jobs. If any buildup of earth formed in front of the
roller wheels two tractors were required, one pulling and one
pushing. After the surface ironed out, one could haul it forward
but could not begin to back it without jack-knifing, so the rear
tractor on a quick cable hookup was used as it could be quickly
unhooked and used as a pusher if necessary. Did all this pay off?
Yes, after 24 years of use by yesteryear’s planes, the B52 is
now becoming obsolete, and after today’s larger planes, this
runway held up remarkably well.
The locale is Westover Field, Chicopee Falls, Mass. The
construction is a 300 X 10,000 foot (three hundred plus feet wide
and 10,000 feet long) runway with a 1,000 foot paved overrun on
each end, actually over 2 miles long, with one of the world’s
largest hangers, fuel tank farm and pumping facilities. The time
1954-1956. Yours truly was resident engineer in charge.
