1. CE 515 Railroad Engineering
Railway Electrification
AREMA Chapter 9
Image: Ohio State University
“Transportation exists to conquer space and time -”

2. Electric Traction Development
1835: Thomas Davenport – developed electric railway using a model railroad with a third rail
1879: Werner von Siemens – first practical electric railway
1890: Siemens' brothers - London underground railway (two 50 hp motors)
1898: Arthur Koppel - introduced mass production battery and electric locomotive in the US
Image: Getty (under fair use)
Image: Mike’s Rail History prior to 1935
Image: Mike’s Rail History prior to 1935
Image: Scientific America Supplement

3. Electric Traction Development
1895: first electric train in the US
Power was supplied at 550 to 675 VDC
1905: Railways started using and converting DC to AC power with up to 25 kV
Example of power used in the US:
High speed: 12.5 – 25 kV
Heavy haul: 25 – 50 kV
Commuter: 650 – 12 kV
Most efficient found in 1960s was 25 kV
Image: 1902, viewliner LTD
Image: Eric, 2009
Image: City of Montreal

4. Electric over Diesel-Electric
Straight-Electric Advantages:
Higher speeds and low-end torque
Able to utilize multiple power sources (coal, nuclear, hydroelectric)
Minimize local air emissions
Can employ regenerative braking to add electricity to the grid
Can improve capacity without adding infrastructure
Diesel-Electric Advantages:
Lower initial capital cost
Does not require elaborate electrical grid system
Can operate during any power state and in areas where power cannot be reached easily
Minimizes electrical safety hazards to the public with no exposed high-voltage rails or wires.

5. Existing Electrification Systems
Inter-City
Heavy Haul
Commuter Rail
Metrorail
Light Rail
Street Car
Advance Light Rapid Transit
Image: Eric
Image: Metro
Image: MARC
Image: RTD
Image: City of Toronto
Image: University of West Virginia

6. Elements of an Electrification System
Sources of primary power
Substations to transform the power into a form suitable for train operations
Power distribution system
Current collectors to draw the power

7. Sources of Primary Power
Railways will receive electrical power from multiple sources
Coal, nuclear, hydroelectric
Railroads rarely will generate own electricity
AC and DC power substations provide one level of redundancy
Two transformers will power two different sections so one can be taken offline for maintenance
DC substations use a rectifier transformer to step down and convert AC power
Distribution system:
Feeder cables (power distribution to contact system)
Negative return cables (attached to the rails)
Contact system

8. Power Distribution Systems
Third Rail Power System
Rigid and mounted parallel to the track on sleeper ties using an insulator
terminated at rail crossings, turnouts, and diamonds
Issues experienced include:
Icing, limited voltage, stray return currents the leak into the ground
Catenary Power System
Catenary wire and contact wire(s)
One or two contact wires in tension
Breaks allow for maintenance
Return wire connected to the rail complete the circuit
Image: FHWA 2005
Image: RTD

9. Power Collection Systems
Contact Shoe
For third rail systems
Overrunning, under, and side
Trolley Poles and Pantographs
For overhead catenary systems
Single pole, diamond, z-shaped
Consist of a wide carbon rubbing strip
6 ft. 6 inches above the rain with a 4 ft. 4 inch rubbing strip
High tension contact
In tension to prevent
Pantograph oscillation
Images: southernelectric.org.uk, how stuff works, flicker
Images: RTD, njrail.com

10. Signals and Communication
Trains are detected through electrical track circuits of the train control system
Signaling systems cannot work if the rails are used as negative returns
An impedance bond connects to the tracks across the insulated joint
Allows traction current to pass through while keeping the signaling system track circuit separated
Images: railroad.net