TM 55-2200-001-12
Change 1
Section 1-General Rules (Rev.-11-1978)
RECOMMENDED PROCEDURES FOR CONDUOTING FIELD IMPACT TESTS OF LOADED
OPEN TOP OARS-(Concluded)
5. PROCEDURE
The specimen car carrying test load should be pulled a sufficient distance from the buffer cars. The test load car
is then pushed toward the buffer cars until the desired speed is obtained and then released and allowed to roll freely into
the buffer cars having knuckles positioned for coupling.
There should be four impacts of the test loads. The first three at 4, 6, and 8 miles per hour, respectively, (track
speeds of test car), in the same direction and as described above. The first two impacts shall be approximately 4 and 6
miles per hour, respectively, whereas, the third and fourth impacts must equal or exceed 8 miles per hour.
The fourth impact, at 8 miles per hour, shall be at opposite end of test car from the first three impacts. If it is not
possible to turn test car, because of track layout, this may be accomplished by running test load car to opposite end of
buffer cars, impacting as above.
If above conditions for fourth impact are impossible, then a loaded car having a total weight on rail equal to or
exceeding weight of test load car may be used as a striking car. (This striking car preferably should be a gondola loaded
with ballast, sand, or gravel, et cetera). The test load car must be placed clear of other equipment with air and hand
brakes set. This fourth test at 8 miles per hour will impact the striking car against the test load car.
If readjustment of lading or reconditioning of bracing or items of securement is permitted during the impact tests,
testing will stop and a complete new impact test initiated.
6. RECORD OF TESTS
An accurate record of the tests is to be maintained, tabulating the number and speed of impacts, and
observations of blocking and lading after each impact.
IMPACT SPEED CONVERSION TABLE FOR 50 FEET TRAVEL
TIME
SPEED
TIME
SPEED
TIME
SPEED
TIME SPEED
SECS. MPH
SECS. MPH
SECS. MPH
SECS. MPH
2.0
-
17.05
4.0
-
8.52
6.0
-
5.68
8.0
-
4.26
2.1
-
16.23
4.1
-
8.31
6.1
-
5.59
8.1
-
4.21
2.2
-
15.50
4.2
-
8.12
6.2
-
5.50
8.2
-
4.16
2.3
-
14.82
4.3
-
7.93
6.3
-
5.41
8.3
-
4.11
2.4
-
14.20
4.4
-
7.75
6.4
-
5.35
8.4
-
4.06
2.5
-
13.64
4.5
-
7.58
6.5
-
5.24
8.5
-
4.01
2.6
-
13.11
4.6
-
7.41
6.6
-
5.17
8.6
-
3.96
2.7
-
12.62
4.7
-
7.25
6.7
-
5.09
8.7
-
3.92
2.8
-
12.17
4.8
-
7.10
6.8
-
5.01
8.8
-
3.87
2.9
-
11.76
4.9
-
6.96
6.9
-
4.94
8.9
-
3.83
3.0
-
11.36
5.0
-
6.82
7.0
-
4.87
9.0
-
3.79
3.1
-
11.00
5.1
-
6.68
7.1
-
4.80
9.1
-
3.75
3.2
-
10.65
5.2
-
6.56
7.2
-
4.73
9.2
-
3.71
3.3
-
10.33
5.3
-
6.43
7.3
-
4.67
9.3
-
3.67
3.4
-
10.03
5.4
-
6.31
7.4
-
4.61
9.4
-
3.63
3.5
-
9.74
5.5
-
6.20
7.5
-
4.55
9.5
-
3.59
3.6
-
9.47
5.6
-
6.09
7.6
-
4.49
9.6
-
3.55
3.7
-
9.21
5.7
-
5.98
7.7
-
4.43
9.7
-
3.51
3.8
-
8.97
5.8
-
5.88
7.8
-
4.37
9.8
-
3.48
3.9
-
8.74
5.9
-
5.78
7.9
-
4.32
9.9
-
3.44
10.0
-
3.41
D-45
