TM 55-2200-001-12
Change 1
Section 1-General Rules (Rev.-11-1978)
RECOMMENDED PROCEDURES FOR CONDUCTING FIELD IMPACT TESTS OF LOADED
OPEN TOP CARS
1. SCOPE
(a)
This method is intended only for practical tests in the field to evaluate loading and bracing of lading in or on open
top cars.
2. EQUIPMENT
(a)
The specimen load car should be representative of the type car intended for use in transporting the commodity
under tests and, unless otherwise agreed to, cars are to be equipped with standard draft gears and conventional
underframe.
(b)
Five empty cars are selected as the buffer or struck cars. Loaded cars may also be used. in either case, the
total weight of the buffer cars is to be approximately 250,000 lbs.
(c)
One locomotive.
(d)
A minimum of 200 ft. length of reasonably level tangent track between the buffer cars and the test car is
required to attain speeds for impact testing before accelerating locomotive for testing.
(e)
Speed measurement devices, any one of the following is acceptable.
1.
Electric timers.
2.
Stop watches (min. 2), and torpedoes, toy torpedoes preferred (min. 8). Stop watches to have a
minimum readable subdivision for 1/5 second.
3.
Radar equipment
(f)
If desired, impact registers may be used as a performance check. They should not be used as speed recorders
When used, the registers must be nailed to the car floor and tapes marked and recorded after each impact.
3. PREPARATION
The test load or loads must be prepared specimens representative of the intended loading and bracing method.
The arrangement of articles or containers and the bracing securement of them must be identical to the contemplated
procedure. If safety or other reasons preclude the use of actual commodity, the specimen must be equal in weight and
general character to the materials to be shipped.
4. ARRANGEMENT OF TEST EQUIPMENT
(a)
Place buffer cars at far end of track and set air and hand brakes. Struck end of first buffer car must have
standard draft gear.
(b)
Locate test car between buffer cars and locomotive.
(c)
Brief train crew on the procedure. Delegate one person to advise appropriate member of the train crew in regard
to when moves are to be made. All participants and observers should be instructed to take precaution for their personal
safety and observe safety practices of the carrier and/or company conducting tests. If desirable, train crews should have
a test run without impacting the test load to establish accuracy of speed.
(d)
Electric timer: Place switch contacts on track in accordance with manufacturers instructions.
(e)
When stop watch and torpedoes are employed to obtain speeds, measure torpedo locations. The first torpedo
shall be placed beyond face of knuckle on first buffer car and located one foot more than the distance between the center
of the leading wheels and knuckle face of test car. The second torpedo shall be 50 feet along track from the first
torpedo. The relationship of time lapse speed for travel of distance for 50 feet is shown on chart, Figure No. 1.
(f)
Radar equipment: Position radar scanner in a appropriate location and follow manufacturers instructions.
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