Assiut University Mine Machinery
Faculty of Eng. 4th year
Mining & Metall. Dept. 2020-2021
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Transportation by locomotives
(1) A train of 13 cars, each with capacity of 3 ton and a tare weight of 1.2 tons, is
to be hauled along a road having a maximum gradient of 1 in 100 against the load
by a diesel locomotive at a speed of 9 m.p.h starting, running resistance of cars =
20, 12 lb/ton, starting , running resistance of locomotive = 25, 15 lb/ton,
acceleration = 0.2 mphps, motor efficiency = 0.85. determine the weight and h.p.
of the locomotive required.
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(2) What size and type of locomotive would be installed to deal. with an output of
800 tons per shift along a road 1500 yd. in length rising 1 in 80 against the load?
Time of shift = 8 hr
Starting, running resistance of cars = 15, 10 lb/ton
Starting, running resistance of locomotive = 20, 15 lb/ton
Average, maximum speed = 6.9 m.p.h
Acceleration = 0.2 m.p.h.p.s.
The mine cars in use weighting 30 cwt., carry 3 tons of coal. Motor efficiency =
0.85, allowance time/ each end = 5 min.
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(3) What size and type of locomotive should be used to transport an output of 600
tons per shift along a main road 2000 yd. in length rising 1 in 150 against the load?
The car in use weight 30 cwt., carry 3 tons of coal.
Starting, running resistance of cars = 15, 10 lb/ton
Maximum, average speed =10, 8 m.p.h
Time of shift = 8 hr
Starting, running resistance of locomotive = 20, 15 lb/ton
Acceleration = 0.2 m.p.h.p.s
Motor efficiency = 0.85
Allowance time/each end = 5 min.
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(4) A 5 ton locomotive with steel-tread wheels has been selected to haul a 40 ton
trailing load up a 1% grade. Is it large enough to stop the train on a -2% grade with
deceleration of 0.1 m.p.h.p.s if you are given the following data:
a- coefficient of adhesion when braking = 0.16
b- Cars are plain bearing, R = 30 lb/ton
c- RL = 20 lb/ton
Calculate the braking force.
(5) An output of 60 tons per trainload is to hauled in:
a- mine cars carrying 3 ton per train-load is to be hauled in having a rolling
resistance of 12 lb/ton.
b- tubs carrying 15 cwt. with plain bearings having a rolling resistance of 45
lb/ton.
Determine the respective ideal gradients if the locomotive used in each case
weighs 10 ton.
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(6) A train of loaded mine cars with a gross weight 80 ton is hauled by a
locomotive weighing 10 ton at a speed of 6 m.p.h. the train descends a gradient of
1 in 80. If the rolling resistance of the cars and locomotive respectively are 12&15
lb/ton, determine the retardation produced and the stopping distance after the
brakes have been fully applied.
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(7) What size and type of locomotive would be installed to deal with an output of
800 tons/shift along a road 1500 yd. in length rising 1 in 80 against the load?
Mine cars in use = 30 cwt., carry 3 tons coal
Starting, running resistance of cars = 15.10 lb/ton
Starting, running resistance of locomotive = 25.15 lb/ton
Loading &unloading time/each end = 5 min.
Maximum, average speed = 8.10 m.p.h
Acceleration = 0.1 m.p.h.p.s.
Adhesion coefficient = 0.25
Time of shift = 7 hr
Motor efficiency = 0.85
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(8) given the following conditions to select a locomotive and battery to perform
the work:
a- haulage time = 6hr.
b- tons to be handled/shift = 1200
c- cars, tare weight = 3000 lb, bearing =plain
d- weight of ore per car = 6000 lb.
e- cars per trip = 10
f – steel-tired locomotive
g – speed, maximum = 3.5 m.p.h & average = 2.5 m.p.h
h- length of haul
1) 600 ft of +1% grade
2) 800 ft of -0.75 % grade
3) 200 ft of level track
i-friction allowance
1) Locomotive 20 lb/ton
2) cars 30 lb/ton
3) grade 20 lb/ton
k- factor of safety for battery 10%
l – acceleration 0.1 m.p.h.p.s
m- motor efficiency 0.85
n- allowance time per each end 5 min
