CE 515 Railroad Engineering

Operations of Railways

“Transportation exists to conquer space and time -”

Safety

• FRA responsible for safety

• Safety never deregulated

• All accidents reported

• Safety and Loss Control Department

Tracks

• Main tracks: governed by one or more methods of control.

Should not be occupied without permission or authority

• Other than main tracks: occupancy without authority, the

locomotive engineer should look for other movements,

usually max 20mph

Speed

• Higher speed: improve capacity and productivity but

also risk and maintenance cost

• Separate speed according to the type of train

• Temporary Speed Restrictions (TSR) and Permanent

Speed Restrictions (PSR)

Rail Traffic Control Systems

• Track Warrant Control (TWC)

• Direct Traffic Control (DTC)

• Automatic Block Signal (ABS)

• Centralized Traffic Control (CTC)

Rail Traffic Control Systems

• TWC, DTC: Non-signalized systems

• Use radio communication and computers

• Rail Traffic Controller (RTC): order transferred

by radio and written by crew

Automatic Block Signal (ABS)

• Series of consecutive blocks governed by block signals, cab signals, or both. Signals activated by a train moving through the block, or by certain conditions that affect the block use.

• Developed in 1872, Dr. William Robinson

• Divide “tracks” into blocks, only one train per block

• Directional operations, two or more tracks

• Designated current of traffic, low-density single tracks

Automatic Block Signal (ABS)

• Track circuit• Fail-safe design• Length of block: equal to longest normal

stopping distance • “Two-block, three-indication”, “Three-block,

four-indication”• Remained ABS systems: operated by TWC

rules

Automatic Block Signal (ABS)

http://www.youtube.com/watch?v=U8yGNKH2t3g

Centralized Traffic Control (CTC)

• Track territories, double track sections: crossing

over is allowed.

• Rail Traffic Control Center: all track circuits

connected, controlled together

• Panel: showing position of each train

Centralized Traffic Control (CTC)

http://mysite.du.edu/~jcalvert/railway/ctc.htm

Centralized Traffic Control (CTC)

Centralized Traffic Control (CTC)

• Authority to enter a CTC main track: by signal.

• Crew requests for permission by radio

• Opposing movements: not allowed, only following

train movements

• “Intermediate signals”: facilitate fleeting of trains

Centralized Traffic Control (CTC)

• Single track: 70% of capacity of double track

with ABS

• Railways: shift to CTC: excess capacity

Questions?