1. 12.3 Moving Freight by Rail
Chapter objectives covered in CE361: By the end of this chapter the student will be able to:
Describe intermodal operation between rail and truck work
Compute rail resistance and locomotive power
Staggers Rail Act of 1980: Deregulation of rail road industry

2. 12.3.1 Intermodal Rail/Truck
Roadrailer
Truck Trailers on Flat Car (TOFC)
Containers on Flat Car (COFC)
RRs carry more than 40% of the nation’s intercity freight
RRs carry about 70% of the motor vehicles made by domestic manufacturers.
RRs carry about 64% of the nation’s coal
RRs carry about 40% of the nation’s grain
Chapter 12

3. Intermodal yards TOFC = Trailers on Flat cars
Evolution to more cost effective operations
COFC = Containers on Flat cars
Chapter 12

4. The Increasing Role of Containers
Efficiency of transporting commodities from the manufacturer to retailers helps reduce costs, thus prices.
Standardized container size helped their transfer from one mode to another quicker and easier.
The container movement began with railcars carrying truck trailers on flat cars, called TOFC.
Benefits: No driver needed for a long haul and a large number of trailers can be transported by rail at one time
Disadvantage: The air-space below the trailer is wasted, It increases air-drag, They are non-stackable.
Chapter 12
Truck Trailers on Flat Car (TOFC)

5. A few more benefits and disadvantages of COFC
Containers on Flat Car (COFC) do not have the aerodynamic drag disadvantages that TOFCs have.
Stackable
Energy savings over TOFC
Disadvantage: Required a full truck chassis (that meets the length of containers) at the intermodal yard to go the remainder of the trip by truck.
Containers on Flat Car (COFC)
Intermodal Rail/Truck Yard, SLC
Chapter 12

6. Standard track gauge in the US
Standard gauge in the US = 4 feet 8.5 inches (1,435 mm)
Most narrow-gauge railways are between 600 mm ( 1ft 11 5/8 in) and 1,067 mm (3 ft 6 in).
Chapter 12

7. 12.3.2 Rail Resistance and Locomotive Power
Rail Resistance: For locomotives to pull a train, they must overcome resistance from four main causes:
Eq. 12.1a
Resistance Rtt1, from the weight of the trailing train
Resistance Rtt2, from the aerodynamic drag
Resistance Rgrade, from the ruling grade (steepest grade along the train’s route)
Resistance Rcurve, from the most severe horizontal curve
Eq. 12.1b
Eq. 12.2
Eq. 12.3
w = weight of loaded car per axle (tons)
V = velocity (mph)
K = aerodynamic coefficient
n = number of axles per car
G = ruling grade (percent)
∆ = degree of curvature (degrees)
tt = Trailing ton, lbs/ton
TEdrawbar = Rtotal*C*n*w
TE  Tractive effort
Chapter 12

8. Tractive effort (TE) for draw bars
Chapter 12

9. Total tractive effort required to pull the trailing cars (p.12.17)
Resistance (lbs):
Eq. 12-5
N = No. of enginers
Eq. 12-6
Propulsion:
One HP = 550 ft-lbs/sec
Chapter 12

10. Number of locomotives needed
Resistance of each engine
In this problem grade = level
Chapter 12

11. What if the train runs on a grade?
Max ruling grade? Depends on the length of the train.
Find the speed!
Chapter 12

12. What if the train runs on a grade & on a curve?
Now add a curve…
Chapter 12