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Improving Railroad Classification Terminal Performance Using Concepts of “Lean Railroading”
Jeremiah DirnbergerRailroad Engineering Program
University of Illinois Urbana-Champaign
2
Problem Statement
Inadequate terminal capacity is a barrier to improved service reliability
Building new terminals and/or expanding existing terminals are the most costly alternatives
New methods are needed to harness as much capacity from the existing infrastructure
3
Presentation Outline
1.0 – Define Lean Railroading
2.0 – The Terminal as a Production System
3.0 – Identifying and Understanding the Bottleneck
4.0 – A Quality of Sort Metric for Improved Terminal Management
5.0 – Implementing the Metric
6.0 – Conclusions
4
1.0 – What is “Lean Railroading?”• The adaptation of proven production management
methods to the railroad environment– Lean– Theory of Constraints (TOC)– Statistical Process Control (SPC or six sigma)– Scheduled railroading is key
• Define value for the ultimate customer– “The ideal product for my customer is . . .”
• Then eliminate waste (any activity that does not add value)– Direct waste (“bad railroading”)– Variability (the root of all waste!)
5
The Building BlocksImproved network
efficiency
Increased service reliabilityand value
Increased terminal capacity
Lean Theory of Constraints
Statistical Process Control
Variability reduction Eliminate directwaste
Bottleneckimportance
Factory Physics(the “science of manufacturing”)
Previous railroad reliability studies(FRA, AAR, MIT)
6
Lean Railroading• Lean Railroading is just beginning
– GE Yard Solutions Group – CPR Yard Operations Performance Group– UP VP Continuous Improvement– BNSF Value Engineering Group– The CN Philosophy
• GE estimates dwell time reduction could result in 15-30% terminal capacity improvement
• CPR reports from March 2005-2006:– Average terminal dwell fell 8.7 hours– Average train speed increased 3.6 mph
7
Implementing Lean RailroadingImplementation steps:
0. Eliminate direct waste: Take a fresh look at the terminal system, try to eliminate obvious sources of waste (Value Stream Mapping)
- Rework, car damage, unnecessary motion, yard engine failure, long setups, unnecessary information collection, etc.
1. Swap buffers: Decrease the time buffer by reducing idle time (continuous flow), increase the capacity buffer by improving bottleneck performance
8
Implementing Lean Railroading2. Reduce variability:
a. Address problems in sorting, rework, car damage, down time and setups (apply SPC/”six sigma”)
b. Implement standardized work plansc. Work with network management to increase on-
time arrival of inbound trainsd. Level the production schedule in the yard and set
the network operating plan
3. Continuous improvement:“Once variability is significantly reduced, we can reduce the capacity buffer while continuing to identify and eliminate variability. Only at this point do we begin to make real gains in productivity.”
Spearman (2002) Factory Physics White Paper Series Part II
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2.0 – The Classification Terminal as a Production System
[The Union Pacific] is a “33,000 mile factory – with no roof.”Dick Davidson, 2003Chairman and former CEO
“This situation is analogous to a manager of an automobile assembly plant . . . In the railroad industry, the terminal superintendent is the plant manager and his function is to assemble inbound trains or parts of trains into completed outbound trains.”
Ferguson, 1980AAR No. R-412
10
The Terminal as a Production System
Inbound trains
Methods/procedures
Information
People
Weather
Infrastructure
Equipment
Outbound trains
Services
Information
“Paperwork”
A classification terminal is a factory that makes connections in the form of trains
Enables use of proven production management techniques in the form of Lean Railroading
11
Hump Yard LayoutClassification
tracks (The Bowl)
Hump &hump tower
Departure yard
Arrival yard
UP Centennial YardFt. Worth, TX
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3.0 – Identifying and Understanding the Bottleneck
13
Identifying a Terminal’s BottleneckTr
ain ar
rival Idle
Inboun
d insp
ectio
n Idle
Bowl (i
dle)
Hump s
et-up
Hump
Pull-dow
n Idle
Idle
Power
onBad
orde
r set-
out
Total
cycle
time
Depart
ure
Inspec
tion &
air t
est
Work time (hrs)Idle time (hrs)
71%
29%
Idle (dwell) time (hrs)
Work time (hrs)
Courtesy of Logan (2006) TRB Presentation
Past studies and railroad management also identify the pull-down process as the bottleneck
14
The Pull-Down ProcessThe pull-down process involves blocks of cars being pulled from the bowl and placed together to form outbound trains in the departure tracks
Car flow during pull-down
Hump yard with parallel receiving and departure yards
15
Current Bottleneck Management ExampleAgincourt Yard (CPR) in Toronto uses the hump pusher engine to build trains when the hump would otherwise be idle
Build trains from both ends of the bowl
Class yard (bowl)
Hump
Departure yard
Receiving yard
Bottleneck capacity increased without any additional infrastructure!
2 jobs maxAdd 1 job when hump idleAvg. time in hump
mode = 52.40%
However, this approach doesn’t work in all yard designs
16
Understanding the Pull-Down Process
Departure Yards
• Consists of two major activities:– Coupling– Pulling
• Two methods of making up trains:– Multiple pulls per engine– Single pull per engine
17
Pull-down Cycle Time ComponentsQueue(Wait)
Transport(Pulling)
Start(Bowl)
End(DP Tracks)
Bowl(Coupling)
Yes
NoRework? Placement
(Uncouple)
Bowl time(estimated from PROYARD)
Transport time(Time studies)
Rework time(Time studies)
F (number of cars, joints, gap spacing,
discrepancies)
F (distance, speed, number of engines,
number switches thrown, number of cars,
interference)
F (standing order)
Previous GE study:The most significant factor of transport time is time spent throwing switches
18
Why does rework occur?Factors:
1) “Cherry-picking” high priority cars2) Removing misrouted or mis-sorted
cars
Hypothesis: As bowl volume increases, the number of misroutes and mis-sorts also increases
19
Number of misroutes vs. cars humpedBensenville Yard (CPR), 1/1/2005 to 4/10/2006
0
5
10
15
20
25
30
35
0 200 400 600 800 1000Cars humped per day
Num
ber o
f mis
rout
es p
er d
ay
Misroutes vs. bowl volume
Daily “average” bowl volume
Number of misroutes vs. bowl volumeBensenville Yard (CPR), 1/1/2005 to 4/10/2006
Number of misroutes
per day
20
Improving Bottleneck ManagementAnalyze the immediate upstream process to find ways to decrease the workload of the bottleneck at all yards
Modify the humping process to make the job of the pull-down as easy as possible
21
4.0 – A Quality of Sort Metric for Improved Terminal Management
“I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind. . .”
Lord Kelvin
“You can’t manage what you can’t measure.”Unknown
22
The Bowl Replay Program
Record all cars in the bowl at 0001 mm/dd/yyyy
Add cars humped into
the bowl
Remove cars pulled from
the bowlInclude trim and local/interchange
moves
23
Bowl Replay Start 0001 11/15
24
Bowl Replay 0222 11/15
25
Bowl Replay 0410 11/15
26
The Quality of Sort Metric
Measures how well the cars are being sorted based on their impact on the bottleneck
Car level
Incorrect Sort Rating (ISR) Track level
Bowl level
Measured in number of cars, a lower ISR indicates fewer incorrectly sort cars
27
Car Level ISR
Every car humped is rated against three components
Car ISR = RT + RG + BI
s.t. RT = 0 or αRG = 0 or βBI = 0 or µα + β + µ = 1
Where: RT is right car-right trackRG is right car-right groupBI is block integrity
28
Track Level ISR ExampleThe track level reflects that pull-down process works by track
Track ISR = {∑all cars on track n Car ISR} x TF s.t. TF = δ or η
“Dirty” track → Penalize“Clean” track → Reward
Mechanical and re-hump tracks not multiplied by TF
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Occurrence of Dirty TracksClean and dirty tracks pulled
Bensenville Yard (CPR)
5
4 2
4
0
5
10
15
20
25
30
7-Mar-2006 21-Mar-2006 22-Mar-2006 23-Mar-2006Date of observation
Num
ber o
f tra
cks
Dirty
Clean
30
The Impact of Dirty Tracks
Queue(Wait)
Transport(Pulling)
Start(Bowl)
End(DP Tracks)
Bowl(Coupling)
Yes
NoRework? Placement
(Uncouple)
(3 crews) x (7.25 hours/shift) x (60 min/hour) x (85%) = 1109.25 min available
Bowl, transport time and setup = 90 min → 12.325 pulls per shift
Average rework of dirty tracks = 25 min → 115 min
11 tracks to be pulled: 8 clean, 3 dirtyTotal time = 1065 min
11 tracks to be pulled: 11 cleanTotal time = 990 min
Fixing dirty tracks also creates the potential for more interference among pull-down engines
31
Bowl Level ISR
Reflects overall performance of hump controller in maintaining a “clean” bowl
Bowl ISR = ∑for all tracks except “special” Track ISR
Hypothesis: As bowl volume increases, bowl ISR will increase
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The Bowl Replay Program
ISR Values:- Right Track, α = 0.25- Right Group, β = 0.25- Block Integrity, µ = 0.50- TF “Clean” track, δ = 0.50- TF “Dirty” track, η = S – B where S=number of separations and B = number of blocks
Removed when car pulled from bowl
Trim moves also reflected in program with movement penalty built in
33
Bowl ISR vs. Bowl Volume
Average ISR vs. bowl volume for Alyth Yard, Sept. 13 to 17, 2005
ISR = 0.0021(BV)2 - 1.8156(BV) + 439.14
0
20
40
60
80
100
120
350 400 450 500 550 600 650BV = Bowl volume (number of cars)
Ave
rage
ISR
(num
ber o
f car
s)
34
5.0 – Implementing the Metric Using SPCAlyth Yard X-bar ISRSeptember 13, 2005
0102030405060708090
0:30
2:30
4:30
6:30
8:30
10:30
12:30
14:30
16:30
18:30
20:30
22:30
Time (+15 min)
ISR
UCL = 54.76
Sample size, n=5
Use SPC to track ISR and identify root causes of an excessively dirty bowl or tracks
Process is outside of upper control limit
35
Implementing the Metric –Potential Optimization Framework
Min ISR
s.t. Car Length (Track) < Remain ∑ Tracks Chosen = 1Mechanical tracks = 0
ISR = Right Car-Right Track + Block Integrity(Based on the current state of the group or bowl)
Decision support systems can be designed based on the Quality of Sort metric
36
Improved Bottleneck Management
• The hump is not the constraint on the system– Correct misroutes and mis-sorts when they occur– Consider the benefits of re-humping– Management should emphasize quality in addition
to quantity
• Better coordination of the pull-down crews– Dedicated pull-down yardmaster– Standardized work, training, remote switch
machines
37
6.0 – Conclusions
• Like many production systems, terminals focus too much on quantity and not enough on quality
• The ISR should be used in a yard management system to add a needed quality component to terminal performance management
• This work provides an illustration of the potential of Lean Railroading
• Lean can be applied throughout the railroad system
38
Railroad Support
• CN: Funding, access to network operations personnel, yard site visits (Champaign, Toronto), hump data and yard simulation models
• CPR: Sponsored site visits and observations (Calgary, Toronto, Chicago), access to network operations personnel, TYES and PROYARD data, research and program feedback from YOP group and yard personnel, a job after graduation
Research Fellowship
39
Railroad Support
• UP: Roseville yard site visit and program feedback
• BNSF: Denver yard background site visit
• NS: Decatur yard background site visit
40
• UIUC: -Dr. Chris Barkan (Advisor)-Darwin Schafer, Justin Wood, Ahsan Alvi(Undergrad Assistants)-Rapik Saat (fellow Graduate Assistant)
• CPR: -Jeff Adams and the entire YOP Group-The Bensenville Yard Team-The Alyth Yard Team-The Agincourt Yard Team
• CN: -Mack Barker, Mike Meleskie-The MacMillian Yard Team-Merle Metz at Champaign Yard
• Prescott Logan of GE Yard Solutions
Acknowledgements