Flower Street Memo

Dl\AJMllHARRIS

~ Mid City/Exposition Light Rail Transit Project Preliminary Engineering Services

Booz Allen Hamilton Inc.

Contract No. EOO16

Corrpro Companies,

Ine.

Diaz Yourman & Assodates Egis-Semafy Inc. Gateway Science & Engineering Harris Miller Miller & Hanson Inc. Jackie Patterson & Associates KAKU Assodates,

Inc.

Kal Krishnan Consulting

June 4, 2003

Melendrez

Services, Inc.

Design Partners

Myra L Frank & Associates, fne. Psomas The Robert Group Zimmer Gunsul Frasca Partnership

Mr. Steve Brye Project Manager Los Angeles County Metropolitan Transportation Authority One Gateway Plaza Los Angeles, CA 90012-2952

Subject:

Project 046105843.0002 LOT No. 0117

Exposition Light Rail Transit Project - Contract No. E0016 Exposition Line Operation Simulation Results

Dear Mr. Brye: The computer simulations of the Locally Preferred Alternative (LPA) and other shared use Blue Line and Expo Line operations have been completed. As described in the LPA, both the Blue Line and the Expo Line have been modeled with five-minute peak: headways on the proposed Hill Street alignment. We have also modeled these headways on the proposed Flower Street alignment. Due to operating conditions that result in unacceptable vehicular traffic disruptions at the Hill Street and Washington Street intersection the Hill Street option has been omitted from further discussion in this letter. During the process of exploring operating options for the Expo Line, it was discovered that the MTA intends to implement a four-minute headway on the Blue Line in 2009, as documented by the MTA Rail Fleet Management Plan dated January 31,2003. To account for this, simulations have also been conducted to show the impacts of operating a four-minute peak: headway on the Blue Line while operating a five-minute peak: headway on the Expo Line. It is important to note that these two headways are fundamentally incompatible and result in significant and regular operating delays. The results of these operating simulations indicate that there are significant challenges to the operation of both lines concurrently through the Flower Street and Washington Street intersection. In addition, there is strong evidence that the current configuration of the 7th & Metro Center terminal will not provide sufficient capacity to meet the needs of both the Blue Line and the Expo Line, and provide MTA Operations with the needed flexibility to respond to operating contingencies. Our analysis indicates that under normal operating conditions the capacity constraints may be manageable with disciplined operations using the five-minute headway identified in the LPA. However the practice will result in operational delays and sacrifice the flexibility that the MTA needs to regulate headways and mitigate technical failures and delays. It is clear that a reduction of the Blue Line's headway to four-minutes will make shared use of the terminal in its current track and platform arrangements insufficiently reliable for good operating practice. These results have been shared on separate occasions with staff from the MTA's Engineering and Operations Departments and have been met with general concurrence. The findings of our analysis are documented in more detail below, organized by the particular areas of concern. At the conclusion of each of the discussions

707 Wilshire Boulevard,

Suite 3300

•

Los Angeles, California, 90017

•

Tel (213) 922-9500

•

Fax (213) 922-9559

Mr. Steve Brye June 4, 2003 Page 2 of4

Mid City/Exposition LRT Project PETeam

we have included potential design modifications that may serve to mitigate or eliminate the current challenges and may merit further investigation. Flower Street and Washington Street Intersection Light rail operations have been simulated with the Expo Line operating at a five-minute headway and the Blue Line operating at both a five-minute headway and a four-minute headway. As simulated with both lines operating on a five-minute headway, the delays experienced by Blue Line trains operating during the PM peak period at the Flower and Washington intersection range from zero to 80 seconds with an average of around 30 seconds. Under the current operating conditions, as observed empirically, Blue Line trains are extremely challenged to hold schedules and maintain consistent five-minute headways during peak operations. It is not uncommon for pairs of trains to be observed entering the Metro Center Station at headways as short as 90 seconds. In the event that the first train in a pair of trains operating at a 90 second headway were held at the Flower and Washington intersection, the second train would be unable to advance to the platform of the Grand Station for over a minute and a half. In fact, due to the train length of approximately 270 feet, the second train would be forced to wait as far back as the Main Street intersection before proceeding. This occurrence has the potential to impact Blue Line operations along the entire portion of street running. This scenario becomes more likely with the advent of four-minute headways operating on the Blue Line while the Expo Line maintains five-minute headways. The combination of a four-minute headway with a fiveminute headway will ensure that even under the best conditions, trains will be delayed by an intersection meet approximately every 20-minutes. On the Expo Line, with both lines operating a five-minute headway, delays experienced at the intersection are much worse than those of the Blue Line. The delays range from zero to 191 seconds with an average of 51 seconds. While traffic signal delays in street running may be routinely as long a 60 seconds, a delay of over three minutes is considered extremely long. This worst-case delay is generated when a northbound Blue Line train holds the signal and is met by a Southbound Blue Line train just after clearing the intersection. This is an occurrence that becomes more likely in the advent of four-minute headways on the Blue Line. There are several options that merit consideration in trying to mitigate or eliminate these intersection conflicts. These options include: •

The use of train-to-wayside communications in combination with a vehicle identification system and traffic signal preemption to control the intersection and assign priority to trains in order to reduce conflicts and increase intersection throughput. This option is likely to be technically challenging and may result in only partial improvements.

•

The use of a half grade separation on the Expo Line to eliminate the diamond crossover.

•

The use of aggressive pre-emption of traffic signals along the street running portion of the Blue Line in order to properly meter and maintain headways. This option may have significant impacts on vehicular traffic and may be met with significant resistance by the LADOT.

•

The use of a separate alignment.

Mr. Steve Brye June 4, 2003 Page 3 of4

& Metro

7th

Mid City/Exposition LRT Project PETeam

Center Terminal

Currently, during the PM peak, the 7th & Metro Center Terminal operates at an effective headway of fiveminutes, accommodating 12 trains per hour. Due to the street running portion of the alignment, this effective headway of five-minutes varies significantly from schedule. Trains were observed to routinely arrive at the terminal as close together as 90 seconds and as far apart as nine minutes. Additionally, MTA operations uses significant platform and pocket track dwells to maintain a proper schedule for the departure of southbound Blue Line trains. Both of these factors combine to require the routine use of both platforms and pocket tracks to regulate Blue Line operations. The terminal simulations determined that when using a headway of five-minutes for both the Blue Line and the Expo Line, the best operating scenario is to dedicate a platform to the operation of each line. Under this scenario, each train enters the terminal and berths at its designated platform, (e.g., platform #1 for the Blue Line, platform #2 for the Expo Line). At the platform, the train dwells for 60 seconds while passengers alight and board, and a drop back operator assumes control of the train from the departing end. This operating scenario eliminates the use of the pocket tracks in routine operations and leaves one free to accommodate a spare train. The results of this simulation indicate that trains on the Blue Line may experience total delays entering and leaving the terminal of up to 96 seconds while Expo Line trains experience delays of up to 62 seconds. More critically, the delays experienced by inbound passengers awaiting access to the terminal platform may be as high as 60 seconds for the Blue Line. While this simulation may accommodate both lines with manageable delays, it ignores several operating factors that decrease the capacity ofMT A operations to recover from contingencies and regulate operations: •

The maximum dwell of 60 seconds means that trains will depart from the terminal at essentially the same headways at which they arrived. In some instances this may be as close as 90 seconds, which will impair the MTA's ability to reestablish proper headways

•

A train that needs to be taken out of revenue service will exceed the minimum dwell, which may cause delays in excess of those mentioned in the preceding paragraph, depending on the nominal headway of the following train

•

Under the current configuration, the tail tracks can only accommodate one spare train that must cover operations for both lines because one tail track must be left vacant to accommodate any being removed from service

•

Any technical problems experienced in or around the platforms and the front crossover may result in serious or non-recoverable delays to Expo and or Blue Line operations.

There are several options that merit consideration in trying to mitigate or eliminate these terminal restraints. These options include: •

The use of aggressive pre-emption of traffic signals along the length of the Blue Line in order to properly meter and maintain headways. Again, an option that is likely to be unacceptable to the LADOT

•

The use of advanced communications systems to determine and respond to variations in nominal headways by varying platform dwells. A solution that may result in improvements to normal operations but will do little to provide relief or recovery from unusual operating contingencies

Mid City/Exposition LRT Project PETeam

Mr. Steve Brye June 4, 2003 Page 4 of4

•

Extending the existing tail-tracks to accommodate an additional train

•

The construction of a third platform track at the terminal

•

A separate alignment.

Recommendations The PE Team believes that the results of our analysis as described herein suggest a change in emphasis on the Branching Study in order to ensure that a viable Exposition Corridor Project is developed. We propose the following: 1.

Further analysis of the Hill Street alternative be halted, based upon the untenable shared use delays likely to be experienced by Blue Line service, Expo service, and area automobile traffic.

2.

Further analysis of the Flower Street alternative be suspended, pending the results of No. 4 below, based upon the untenable shared use delays likely to be experienced by Blue Line service and Expo servICe.

3.

Further analysis of the Figueroa Street alternative be directed towards a surface alternative terminating in the vicinity of 7th and Flower, most probably in the parking lot behind the 818 Building.

4.

New analysis of physical improvements to the 7th and Flower Street Station and the junction of the Blue Line and Expo Line services be modeled and ROM costed. At the present time, the PE team feels three potential modifications should be evaluated; a) the addition of a third track, effectively creating a center platform configuration for one of the existing Blue Line platforms b) the extension of the tail tracks northward under Flower, creating additional storage capacity to stage trains c) the addition of half grade separated operations in the vicinity of Washington Street

The PE team is available to discuss these recommendations and the supporting analysis. We are aware of the importance of these decisions to the project. We believe a rapid decision on these recommendations is vital to our achieving the overall project schedule. Sincerely,

Step~echronis Project Director

cc: EssamAly Al Witzig Aaron Foresman Chron file

Matt Sweeney Eric Olson Michael Harris-Gifford Project files 202.2, 491.3