BL service increase is possible with SV line

With all the uproar over the cuts to the silver line I took it to look at operations and came up with the following solution: BL/OR/SV trains operate at 8 min headways on individual branches during rush hour. In the core operate in a 2/2/4 pattern with the larger gap falling between SV & BL

This would give roughly 7 trains per hour for each line for a total of 21 TPH way under the threshold. Based on ridership trippers could feel the gap of 5 more TPH that's available.

"DiscoveryAnalysis"

With all the uproar over the cuts to the silver line I took it to look at operations and came up with the following solution: BL/OR/SV trains operate at 8 min headways on individual branches during rush hour. In the core operate in a 2/2/4 pattern with the larger gap falling between SV & BL

This would give roughly 7 trains per hour for each line for a total of 21 TPH way under the threshold. Based on ridership trippers could feel the gap of 5 more TPH that's available.

You got it wrong, trains in the core will run at roughly 2 minutes and 30 seconds headways during peak regardless of color, not sure what the sequence will be:
OR, SV, BL, OR, SV, OR, BL, SV, OR, SV, BL, OR, SV or
SV, OR, BL, SV, OR, SV, OR, BL, SV, OR, SV, OR, BL, SV, OR or
OR, SV, BL, OR, SV, OR, SV, BL, OR, SV, OR, SV, BL, OR, SV

The extended gap in the headways to accommodate the Blue line will be between Rosslyn and Vienna and Stadumn - Armory and New Carrollton. On the east side the losers will be Orange line users as 2 out of 3 trains will be going to Largo.

Sand Box John wrote:"DiscoveryAnalysis"

With all the uproar over the cuts to the silver line I took it to look at operations and came up with the following solution: BL/OR/SV trains operate at 8 min headways on individual branches during rush hour. In the core operate in a 2/2/4 pattern with the larger gap falling between SV & BL

This would give roughly 7 trains per hour for each line for a total of 21 TPH way under the threshold. Based on ridership trippers could feel the gap of 5 more TPH that's available.

You got it wrong, trains in the core will run at roughly 2 minutes and 30 seconds headways during peak regardless of color, not sure what the sequence will be:
OR, SV, BL, OR, SV, OR, BL, SV, OR, SV, BL, OR, SV or
SV, OR, BL, SV, OR, SV, OR, BL, SV, OR, SV, OR, BL, SV, OR or
OR, SV, BL, OR, SV, OR, SV, BL, OR, SV, OR, SV, BL, OR, SV

The extended gap in the headways to accommodate the Blue line will be between Rosslyn and Vienna and Stadumn - Armory and New Carrollton. On the east side the losers will be Orange line users as 2 out of 3 trains will be going to Largo.

SBJ that's WMATA plan. What I was suggesting is completely different scheduling.....
Example - Metro Center TRK 2 at 5:00 PM

5:00 SV Reston East.
5:04 BL Franconia-Springfield
5:06 OR Vienna
5:08 SV Reston East
5:12 BL Franconia-Springfield
5:14 OR Vienna
5:16 SV Reston East
5:20 BL Franconia-Springfield

And Eastbound would be taking a page from rush plus,

5:00 SV Largo Town Ctr
5:02 OR New Carrollton
5:04 BL Largo Town Ctr
5:08 SV New Carrollton
5:10 OR New Carrollton
5:12 BL Largo Town Ctr
5:16 SV Largo Town Ctr
5:18 OR New Carrollton
5:20 BL Largo Town Ctr
5:24 SV New Carrollton
5:26 OR New Carrollton
5:28 BL Largo Town Ctr
5:32 SV Largo Town Ctr

Metro has announced that up to 50% of rush hour Blue line trains will be 8-cars long. http://www.wmata.com/about_metro/news/P ... aseID=5739

"DiscoveryAnalysis"
SBJ that's WMATA plan. What I was suggesting is completely different scheduling.....
Example - Metro Center TRK 2 at 5:00 PM

5:00 SV Reston East.
5:04 BL Franconia-Springfield
5:06 OR Vienna
5:08 SV Reston East
5:12 BL Franconia-Springfield
5:14 OR Vienna
5:16 SV Reston East
5:20 BL Franconia-Springfield

And Eastbound would be taking a page from rush plus,

5:00 SV Largo Town Ctr
5:02 OR New Carrollton
5:04 BL Largo Town Ctr
5:08 SV New Carrollton
5:10 OR New Carrollton
5:12 BL Largo Town Ctr
5:16 SV Largo Town Ctr
5:18 OR New Carrollton
5:20 BL Largo Town Ctr
5:24 SV New Carrollton
5:26 OR New Carrollton
5:28 BL Largo Town Ctr
5:32 SV Largo Town Ctr

Why the 4 minute gap after Blue line trains? That 4 minute gap put a 6 minute gap in the schedule west of Rosslyn and an 8 minute gap in the Orange line schedule east of Stadium - Armory.

Running trains every 2 1/2 minutes regardless of color through the urban core reduces 6 minute gap west of Rosslyn to 5 minutes and the 8 minute gap on Orange line east of Stadium - Armory to 7 1/2 minutes.

But then the real solution is to procure enough rolling stock to allow headways under 2 minutes.

The need to procure more rolling stock and/or the ability to run trains at 40 tph has been discussed time and again on this forum. For documentation sake, and because I don't recall seeing a firm rationale from WMATA, here's what AGM Lynn Bowersox had to say about 40tph. It fits nicely in this thread since the entire chat was about Silver Line opening and service. (And I suspect some of the questions in the chat were from members here...) This is from her chat with Dr. Gridlock:

Q: TRAINS PER HOUR
Why the hard cap at 26 tph? The system was designed to run 40tph. If you just bought more railcars, you could run all three lines every six minutes with 4tph to spare. So why not push for this?

A: LYNN BOWERSOX :
There was an engineering-led study about 12 or 13 years ago that looked at this issue. The study found that the Metro system can reliably operate a maximum of 26 trains per hour (one every 135 seconds) on each track. While there are certain components of the system, such as certain types of switches, that have a slightly higher design standard, as a practical matter, any more frequent than a train every 2 min 15 seconds would be too tight to ensure reliable service.

The good news is that we are expanding the fleet. Our new 7000-series cars, which are currently going through testing, will not only replace the 1000-series and 4000-series, but also add 128 cars to accommodate ridership growth (Silver Line). We are also looking to exercise an option in the contract next fiscal year to expand the fleet by another 220 cars to get closer to our goal of all 8-car trains during rush hours.

http://live.washingtonpost.com/gridlock ... 12c1cd8d1e

"Mainland"
The need to procure more rolling stock and/or the ability to run trains at 40 tph has been discussed time and again on this forum. For documentation sake, and because I don't recall seeing a firm rationale from WMATA, here's what AGM Lynn Bowersox had to say about 40tph. It fits nicely in this thread since the entire chat was about Silver Line opening and service. (And I suspect some of the questions in the chat were from members here...) This is from her chat with Dr. Gridlock:

Q: TRAINS PER HOUR
Why the hard cap at 26 tph? The system was designed to run 40tph. If you just bought more railcars, you could run all three lines every six minutes with 4tph to spare. So why not push for this?

A: LYNN BOWERSOX :
There was an engineering-led study about 12 or 13 years ago that looked at this issue. The study found that the Metro system can reliably operate a maximum of 26 trains per hour (one every 135 seconds) on each track. While there are certain components of the system, such as certain types of switches, that have a slightly higher design standard, as a practical matter, any more frequent than a train every 2 min 15 seconds would be too tight to ensure reliable service.

The good news is that we are expanding the fleet. Our new 7000-series cars, which are currently going through testing, will not only replace the 1000-series and 4000-series, but also add 128 cars to accommodate ridership growth (Silver Line). We are also looking to exercise an option in the contract next fiscal year to expand the fleet by another 220 cars to get closer to our goal of all 8-car trains during rush hours.

This statement now convinces me that the people running WMATA are suffering from collective amnesia. During the early years WMATA routinely ran trains at near 90 second headways. They did it using terminal interlockings with #8 turnouts and the same #15 turnouts in junctions, all of today's terminal interlockings have #10 turnouts. The only difference between now and then are the length of the trains, the dwell times at stations and train speed. Back then trains were shorter, 4 and 6 cars long, today they are 6 and 8 cars long, station dwell times were under 20 seconds, today they are 30 seconds or more, and trains were run at near maximum performance speeds, today they run at 2/3 to 3/4 of maximum performance speed.

I would like to see the paper from that engineering study.

Sand Box John wrote:
I would like to see the paper from that engineering study.

While not the paper outright, I suspect this may be the firm/study in question.

http://www.systraconsulting.com/expert- ... nalysis-19

http://railsim.com/case-studies.html?cs ... simulator-

That second link puts a date of the study after the extension to Largo - in the ball park of Bowersox's "12 to 13 years" estimate.

What are the Blue Lines "pre SV" headways?

All I know is that the "Save the Blue Line" people are doing the math wrong
as described in this WaPo story, "advocates" are saying 12min headways "costs" them two vacation days. This is absurd. First, with 12 min headways, you wait, on average about 6 minutes.

Second the "cost" of service reductions isn't against "no wait" (possible only with moving sidewalks , rather it is against the current wait, which I guess to be in the 4min range (assuming 8min headways)
So going from 8min headways to 12min headways "costs" you an average of 2 minutes per day--they're overstating the "cost" by 6x.

Sand Box John wrote:Back then trains were shorter, 4 and 6 cars long, today they are 6 and 8 cars long, station dwell times were under 20 seconds, today they are 30 seconds or more, and trains were run at near maximum performance speeds, today they run at 2/3 to 3/4 of maximum performance speed.

They should fix the max speed problem. That's going to be where the big gains are. But to do that, they're also going to have to upgrade the safety & control systems. Haven't Longer trains also mean it is harder to "stick the landing"? Its something like 50 times harder to properly berth an 8-car train vs a 4 car (which have a +/- 1% margin of error vs a 50% margin of error). Rather than maintain/upgrade the automation and safety systems (to maintain the old max speeds), they bought the margin of error for the 8 car trains by slowing the system down.

I don't see long dwell times going away, because while the "average" person gets on or off the same, then or now, regardless of how long a train is, long trains are more at the mercy of "weirdos"--the one runner who fouls the doors getting on, or one sleeper who fouls the doors with a last minute exit. The average passenger isn't any weirder these days, but the average long train is going to have more weirdos perturbing it than a short train--and all it takes is one weirdo to cost you a whole 5-10 second door cycling. (Crowded platforms will have more boarding weirdos, regardless of train length, so part of what the trains suffer comes from ever-higher volumes, and the total capacity of trains--not, strictly speaking, their length).

"Mainland"

While not the paper outright, I suspect this may be the firm/study in question.

http://www.systraconsulting.com/expert- ... nalysis-19

http://railsim.com/case-studies.html?cs ... simulator-

That second link puts a date of the study after the extension to Largo - in the ball park of Bowersox's "12 to 13 years" estimate.

Simulations are just that, simulations. Without seeing the date used to create the model and the various scenarios run within that model. I can't totally except their conclusion without seeing what scenarios were run and more importantly what scenarios were not run. We don't know what mean distance between failure mileage they use, we don't know if put ins of trains at the terminal to aid in the recovery of the schedule was in any of the scenarios, we don't know what the size of the fleet they used in the model, we don't know . . .

I'm sill not convinced.

"Arlington"

They should fix the max speed problem. That's going to be where the big gains are. But to do that, they're also going to have to upgrade the safety & control systems. Haven't Longer trains also mean it is harder to "stick the landing"? Its something like 50 times harder to properly berth an 8-car train vs a 4 car (which have a +/- 1% margin of error vs a 50% margin of error). Rather than maintain/upgrade the automation and safety systems (to maintain the old max speeds), they bought the margin of error for the 8 car trains by slowing the system down

The speed issue is not really that important, the time difference for a given run between terminal pairs at different average speeds is not all that great. The Automatic Train Supervision (ATS) part of the train control system uses speed to set and or maintain headway spacing.

It should be noted that the primary reason why speeds were reduced was to reduce the wear and tare on the rolling stock. The 1k cars had the crap run out of the during the first 20 years of their life. That's one of the reasons why they are so fragile.

Sticking the landing as you call it is a matter of maintaining train board equipment to proper calibration. The automatic berthing of trains uses wheel revolutions to calculate the distances between fixed point that tell the train where it is in relationship to the center of the platform. The profile of the wheels changes with wear, as a result the wheels need to be retrued to return them back to the correct profile. the retruing changes the diameter of the wheels. If the train board equipment is not properly calibrated to the diameter wheel be it worn and or retrued it will likely not stick the landing.

About 15 years ago an individual I know that works in the Rail Operation Computer System told me the not sticking of the landing happened at an average rate of 1 in 10,000 train berthings.

I don't see long dwell times going away, because while the "average" person gets on or off the same, then or now, regardless of how long a train is, long trains are more at the mercy of "weirdos"--the one runner who fouls the doors getting on, or one sleeper who fouls the doors with a last minute exit. The average passenger isn't any weirder these days, but the average long train is going to have more weirdos perturbing it than a short train--and all it takes is one weirdo to cost you a whole 5-10 second door cycling. (Crowded platforms will have more boarding weirdos, regardless of train length, so part of what the trains suffer comes from ever-higher volumes, and the total capacity of trains--not, strictly speaking, their length).

Closer headways would reduce the amount of passenger aboard the trains, it would also reduce the amount of passenger on the platforms waiting to board the trains. Those reductions would allow the shortening dwell times with little or no effect to passengers boarding or discharging. As to the "weirdos" as you call them, they should be left to their devices and ignored, WMATA is in the business of moving people not baby sitting lost souls.

Before SV, BL had 7 inbound trains per hour (out of 26 trains), or about 1 BL every 8.6 minutes
After SV, BL will have 5 inbound trains per hour (out of 26 trains) or about 1 BL every 12 minutes.

So the average BL wait time is going from 4.3minutes to 6.0minutes. AN increase of 1.7mins = Roughly a 40% increase in wait time, but amounting to 3.4 minutes per day. 240 work days a year, that's 816 minutes / year, or about 13.6 hours (a workday and a half)

Actually, folks at Vienna are going to suffer too, going from 19 trains per hour (one every 3.2 mins) to 11 trains per hour (one every 5.5 mins). Average wait time at Vienna rises from 1.6mins to 2.7mins.

From Greater Greater Washington:

Right now at Rosslyn during peak hours, there are 19 inbound Orange Line trains and 7 inbound Blue Line trains each hour. That means there's an inbound train about every 2 and a half minutes.

Of the Orange Line trains, about 40% are 8 cars long and 60% are 6 cars. All of the Blue Line trains are currently 6 car trains. That means that each hour at Rosslyn, there are roughly 42 inbound Blue Line cars and 130 inbound Orange Line cars. This means a total of 172 inbound cars per hour.

Once the Silver Line opens, the distribution will change. Starting on July 28, the mix at Rosslyn will be 11 Orange Line trains each hour, 10 Silver Line trains per hour, and 5 Blue Line trains per hour.

All of the Silver Line trains will be 6 cars in length. The proportion of Orange Line cars is not expected to change, so it will remain about 40% 8-car trains. The Blue Line will operate with half of its trains as 8 car sets.

That means that at Rosslyn, there will be 35 Blue Line cars inbound each hour, a reduction of 7 cars. The Orange Line will also see a reduction, with only 74 cars per hour. The Silver Line will have 60 cars inbound each hour

Sand Box John wrote:"DiscoveryAnalysis"
SBJ that's WMATA plan. What I was suggesting is completely different scheduling.....
Example - Metro Center TRK 2 at 5:00 PM

5:00 SV Reston East.
5:04 BL Franconia-Springfield
5:06 OR Vienna
5:08 SV Reston East
5:12 BL Franconia-Springfield
5:14 OR Vienna
5:16 SV Reston East
5:20 BL Franconia-Springfield

And Eastbound would be taking a page from rush plus,

5:00 SV Largo Town Ctr
5:02 OR New Carrollton
5:04 BL Largo Town Ctr
5:08 SV New Carrollton
5:10 OR New Carrollton
5:12 BL Largo Town Ctr
5:16 SV Largo Town Ctr
5:18 OR New Carrollton
5:20 BL Largo Town Ctr
5:24 SV New Carrollton
5:26 OR New Carrollton
5:28 BL Largo Town Ctr
5:32 SV Largo Town Ctr

Why the 4 minute gap after Blue line trains? That 4 minute gap put a 6 minute gap in the schedule west of Rosslyn and an 8 minute gap in the Orange line schedule east of Stadium - Armory.

Running trains every 2 1/2 minutes regardless of color through the urban core reduces 6 minute gap west of Rosslyn to 5 minutes and the 8 minute gap on Orange line east of Stadium - Armory to 7 1/2 minutes.

But then the real solution is to procure enough rolling stock to allow headways under 2 minutes.

The 4 mins behind the BL was intended for a couple of reasons; 1) Allow a buffer to accomadate trains diverging at C05 & D98 without causing trains trailing to lose speed read outs. 2) Creates a buffer during operational delays in which operators or ATS can readjust scheduling headway. And along the stretches heading outbound beyond C05 & D08 there would be relatively few boardings toward the terminals. Given the use of Mode 2 for the next year, and the concern of ATO operation that WMATA will still harbor I don't think they will drop to a 150 second headway schedule.

"DiscoveryAnalysis"
The 4 mins behind the BL was intended for a couple of reasons; 1) Allow a buffer to accomadate trains diverging at C05 & D98 without causing trains trailing to lose speed read outs. 2) Creates a buffer during operational delays in which operators or ATS can readjust scheduling headway. And along the stretches heading outbound beyond C05 & D08 there would be relatively few boardings toward the terminals. Given the use of Mode 2 for the next year, and the concern of ATO operation that WMATA will still harbor I don't think they will drop to a 150 second headway schedule.

Your pissing away time that need not be pissed away. Converging and diverging at D&G junction is not really that big of an issue as trains are moving at speed on either side and through the junction. The only obstacle to converging and diverging movements at C&K junction are trains dwelling at the Rosslyn platform. The turnout in both junction become ready to reset for the route of he next train seconds after a train clears the interlocking track circuit.

In mode 2 ATS becomes less effective because an operator will normally overreact to speed command changes, ATS is more effective in mode 1 because the train board automatic systems respond more smoothly to speed command changes.

If trains are run reasonable close to their assigned scheduled times the 4 minute gap becomes unnecessary. The solution is not to pad the scheduled in anticipation of unforeseen delays, the solution is maintain the rolling stock to a level of reliability that delays become exception not the rule.

Sand Box John wrote:"DiscoveryAnalysis"
The 4 mins behind the BL was intended for a couple of reasons; 1) Allow a buffer to accomadate trains diverging at C05 & D98 without causing trains trailing to lose speed read outs. 2) Creates a buffer during operational delays in which operators or ATS can readjust scheduling headway. And along the stretches heading outbound beyond C05 & D08 there would be relatively few boardings toward the terminals. Given the use of Mode 2 for the next year, and the concern of ATO operation that WMATA will still harbor I don't think they will drop to a 150 second headway schedule.

Your pissing away time that need not be pissed away. Converging and diverging at D&G junction is not really that big of an issue as trains are moving at speed on either side and through the junction. The only obstacle to converging and diverging movements at C&K junction are trains dwelling at the Rosslyn platform. The turnout in both junction become ready to reset for the route of he next train seconds after a train clears the interlocking track circuit.

In mode 2 ATS becomes less effective because an operator will normally overreact to speed command changes, ATS is more effective in mode 1 because the train board automatic systems respond more smoothly to speed command changes.

If trains are run reasonable close to their assigned scheduled times the 4 minute gap becomes unnecessary. The solution is not to pad the scheduled in anticipation of unforeseen delays, the solution is maintain the rolling stock to a level of reliability that delays become exception not the rule.

In the 90s we could get away with 2 min headways with no problems, however Bowersox without directly saying so alluded that the system is no longer reliable and running trains at the max rate will produce delays and even more angry passengers and lower OTP (on time performance), an alternate involves a slight of hand trick. Max out the headways at 90-120 seconds but utilizes 4 car trains.

4 car trains operating at 2-3 min headways have the same load capacity as an 8 car operating at 6 mins. With the appearance of more frequent service without increasing the need of rolling stock.

I also had a recommendation to short turn some BL trains. Operate a 4 pack from Franconia to Rosslyn, crossover at C06 interlocking to TRK2 w/ a drop back operator aboard. Service Rosslyn 2 and reverse back to Franconia. This could be accomplished in the 4 min gap that I created in my timetable earlier. Also it provides a same level transfer for passengers staying in VA.