classes of trains fundamental principles of track authority impact of power/ton ratios drivers of...
TRANSCRIPT
SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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The language of rail operations
Classes of trains Fundamental principles of track authority Impact of power/ton ratios Drivers of dispatch priority
22 September 2010
SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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Fundamentals
A train is a locomotive or locomotives, with or without cars, and displaying markers
Track is a fixed guideway that trains must follow
Two trains shall not occupy a track location at the same time
Must protect track maintenance machines and workers from trains
22 September 2010
SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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Goals of Operating Department
Prevent collisions Train-train Train-mw forces
Accommodate overall traffic demand Avoid unnecessary delay Meet service requirements Minimize train operating costs
22 September 2010
SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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Control System Functions
Facilitate train meets and overtakes Maintain safe spacing between trains Prevent route conflicts Protect maintenance workers/equipment Enforce track speed limits* Alert trains to hazards (e.g., broken rails)* Enforce authority limits *
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* Provided by some types of systems
Operating Both Directions on a Single Track
Overtakes on Single Track
SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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Track Occupancy and Authority
Occupancy: presence of a train or work crew on a track location or section
Authority: permission for a train or work crew to occupy a track
Authority limits: track boundary within which authority is granted (may be directional)
Controlled track: authority granted by a dispatcher, control operator, or procedure
Non-controlled track: authority not required; train crews must avoid conflicting movements
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Granting Authority
Signal-controlled operation Proceed indication
wayside absolute signal cab signal
Written or verbal order from dispatcher permitting train to pass restricting absolute signal permitting maintenance force to occupy track
section Non signal-controlled operation
Timetable modified as needed by train orders Written or verbal order from dispatcher
Supporting Elements
Operating Rules (e.g., GCOR, Norac) Employee timetables Train bulletins Fixed wayside signs (e.g., mileposts,
block boundaries) Signal hardware Voice radio systems Data radio systems
SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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Train Separation
Time based
Distance based
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Distance
Tim
e
Minimum Time Separation
Distance
Tim
e
Blocks
Block occupancytime
SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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Authority Overlaps
Overlap occurs when two trains have simultaneous authority to use a given track segment
May be permissible if trains are traveling in same direction
Never allowable for trains moving in opposite directions
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Must protect against following movements
Assigning Track “Ownership”
Operating AuthorityOperating AuthorityOperating AuthorityOperating AuthorityOperating
Authority
Operating
Authority
Operating AuthorityOperating AuthorityOperating Authority
Types of Trains
Passenger Intercity
High-speed corridor
Long-haul Regional
Commuter Express Local
Freight Intermodal Manifest Unit train
Loaded Empty
Local Company service
Train Characteristics
Train typeLength
(ft)
Max. Speed (mph)
HP/ton
Weight (tons)
Intermodal 6000-8500
60-75 ~2.0 5000-7000
Manifest freight 3000-5000
50-60 0.9-1.2
6000-8000
Bulk commodity 4000-6500
45 0.5-0.9
12000-15000
Local freight 1000-3000
50 0.9-1.2
2000-6000
Long-haul intercity 600-1800 70-90 4.0-6.0
600-1800
Regional intercity 400-600 70-110 4.0-6.0
400-500
Commuter 300-1000 60-90 2.0-10.0
260-900
High-speed corridor
600-700 110-150 10.0 500-600
22 September 2010SCORT/TRB Rail Capacity Workshop
- Jacksonville Florida 14
SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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Influence of Train Power/Weight
The power/weight ratio is an important factor in train performance Maximum speed achievable Acceleration characteristics (time, distance to
reach desired speed) Deceleration on ascending grades
Can alter by adjusting power or train weight Higher value permits better performance,
but generally at greater operating cost Railroad provides sufficient HP to suit
service needs
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Effect of Grade on Operating Speed
0
10
20
30
40
50
60
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5
Grade (%)
Ma
xim
um
Tra
in S
pe
ed
(m
ph
)
P/W = 0.5P/W = 1.0
P/W = 1.5
Effect of P/Won Train Acceleration to 80 mph
P/W 2 4 6 8 10
Distance ToAccelerate(miles)
23.0 7.3 3.6 2.5 1.9
AccelerationTime (min)
23.7 7.7 4.3 3.0 2.3
Time lost (min) 3.7 2.3 1.6 1.2 1.0
Commuter Operating Speeds60-sec. Average Dwell Time
P/WStop every 1 mile 81.3 14.8 69.0 17.4 63.9 18.8Stop every 2 miles 51.5 23.3 43.8 27.4 39.3 30.6Stop every 4 miles 35.5 33.8 29.7 40.4 27.2 44.1Stop every 5 miles 31.8 37.8 26.7 45.0 24.8 48.5
60-SecAvg. Dwell Time
RunTime
AverageSpeed
RunTime
AverageSpeed
RunTime
AverageSpeed
3.0 5.8 9.1
Perfect Single Track Grid
SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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Issues
All trains do not perform equally Acceleration/deceleration Maximum speed
All trains are not the same length Meet/pass locations are not equally spaced All trains are not equally important
Schedule sensitivity Revenue contribution
Traffic is subject to peaks and valleys Track requires outages for maintenance
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SCORT/TRB Rail Capacity Workshop - Jacksonville Florida
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Train Classes
Designate train priority in scheduling and dispatching
Explicit Formal aspect of control system Regular trains (scheduled) receive class designation
(1st, 2nd, 3rd, etc.) Occupancy prioritized by train order, train class, and
direction Implicit
Not formal aspect of control system Occupancy prioritized by factors like train schedule
sensitivity, revenue contribution, and operating performance
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Example of Route-Specific Priority
1. High speed passenger2. Conventional inter-city (corridor or long-
haul)3. Commuter express4. Passenger deadheads5. Intermodal 6. Manifest7. Local commuter8. Bulk unit train9. Local freight
One-Way Flow-Single Train Class
Traffic Direction
Min. Train Separatio
n
Effect of Adding Faster TrainTraffic Direction
Pass Delay