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

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 https://www.youtube.com/watch?v=FoR1Lti1ujE Chapter 12

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

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)

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

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

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

Tractive effort (TE) for draw bars Chapter 12

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

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

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

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