All Things WMATA 7000 Series

dcmike wrote:
The so-called "safe mode" is a great capability that was added to 7000s for good reason. It's not possible to determine whether the loss of traction power is intermittent or more serious, and you don't want to put the train in a configuration that leaves it unable to complete ascending a grade due to insufficient propulsion - or unable to stop rolling back due to insufficient air pressure (loss of traction power also disables the air compressor). Better just to stay put where it's safe.

Hmm, I maybe can see the ascending the grade issue, but other than that....

If you briefly lose traction power on one car in a consist, is that cause enough to trigger a stop? In other words, one car momentarily losing power halts the consist?

I would think that on the steepest grade in the system[1], a reduced number of braked cars could safely hold the consist; the question is what number? I have not looked into 7000 innards enough to know which flavor of them have air compressors or are instead fed from those which do. On a 8 car train, how many compressors are there?

[1] I'm sure Sand Box John will know where that is; the Potomac tube or?

Chris Brown wrote: It would also be nice if they had a system map showing the location of your train on the map. Currently they just show where your train is within a small portion of the line.. which is kind of redundant since the strip map over the windows shows the exact same thing. I actually heard a tourist complain how it doesn't show the entire system map.

I think the kick-ass display would mimic sites we've discussed here showing ALL train locations. And/or when approaching a transfer station, a PEDS-like display of when the other lines will arrive; you'd know if you needed to hustle downstairs to get the Green line you need, etc.

(Getting the data to the trains might be an issue, but it can always use the cellular network when that is complete in ~2099, or the new improved Motorola UHF system that should be working about when the 7000's are retired....)

It seems like the space on the LCD screens is very much underutilized. It shows a handicapped icon for EVERY SINGLE STATION, and they don't go away when there's an elevator outage. Despite having ample space, they do not show the full names of every station, or any relevant information (bus connections available is not the same as saying which routes, to where, and when the next buses will be). Step it up, Metro.

I'm hoping and assuming that the current screen set up is only "introductory" since the 7k's are brand new. Hopefully, as they become a more significant portion of the fleet, the software will be updated to make the screens more useful and passenger friendly.

I think the LED sign at the ends of the cars could be improved too. They should show the date and time like on most buses and maybe a simple weather report too.

"farecard"

Hmm, I maybe can see the ascending the grade issue, but other than that....

If you briefly lose traction power on one car in a consist, is that cause enough to trigger a stop? In other words, one car momentarily losing power halts the consist?

Momentary loss of traction current to one car should not be that big of an issue. An 8 car train has roughly the equivalent horse power of a 6 axle freight locomotive.

I would think that on the steepest grade in the system[1], a reduced number of braked cars could safely hold the consist; the question is what number? I have not looked into 7000 innards enough to know which flavor of them have air compressors or are instead fed from those which do. On a 8 car train, how many compressors are there?

One compressor in each pair, both legacy and 7k cars.

3.5% is around steepest, the rolling stock is spec to be able to climb grades as steep as 5%.

farecard wrote:If you briefly lose traction power on one car in a consist, is that cause enough to trigger a stop? In other words, one car momentarily losing power halts the consist?

That would be a bad design. Trains would not be able to use crossovers if they shut down when one car momentarily lost power.

The cars are designed to cutout a truck's propulsion if the truck detects an unstable power connection, i.e., a long period of arcing between the shoe and the third rail. This is to protect the propulsion package from electrical surge damage. This is the 'safe mode' they speak of.

This only becomes an issue when multiple cars on a consist are affected. Then there are not enough motors to move the train and the train needs assistance.

Anyone know if Metro has started retiring 4k cars yet?

If they plan to be rid of all 1k and 4k cars by the close of 2017 then I would imagine the order in which Metro scraps them would not matter at this point? Now that the 4k's requiring "bellying" in the center of trains.. they have essentially become less reliable versions of the 1k cars. I would expect Metro to move these to the front of the line for retirement.

"Chris Brown"
Anyone know if Metro has started retiring 4k cars yet?

If they plan to be rid of all 1k and 4k cars by the close of 2017 then I would imagine the order in which Metro scraps them would not matter at this point? Now that the 4k's requiring "bellying" in the center of trains.. they have essentially become less reliable versions of the 1k cars. I would expect Metro to move these to the front of the line for retirement.

WMATA will not begin scraping 4k cars until they have at least 364 7k cars in revenue service. Scrapping 4k cars before that would reduce the fleet size below what they had before the 7k cars first hit the property.

One must remember, WMATA has had and sill has a rolling stock shortage that has existed for most of the last 35 years.

How much rolling stock does WMATA need in order to not have a shortage? Will they have the perfect number of rail cars once 100% of the 7k's are delivered?

I heard the 8k series will replace 2k and 3k. Maybe that should be a larger order of at least 500 more cars. Especially if the ultimate goal down the road is 100% 8-car operation at all times on all lines while still having spare cars in the rail yards AND accounting for cars undergoing maintenance and repair.

"Chris Brown"

How much rolling stock does WMATA need in order to not have a shortage?

Depends on who you ask and how many 8 car trains per hour you want put out on the railroad during peak.

Will they have the perfect number of rail cars once 100% of the 7k's are delivered?

Again it depends on who you ask and how many 8 car trains per hour you want put out on the railroad during peak.

In my opinion, no.

The origenal 7k procurement was suppose to increase the fleet size for the Silver line (128), replace the 1k cars (300), do a mid life rehabilitation to the 4k car (100), and add another (220) fleet growth to accommodate all 8 car trains during peak at 24 trains per hour. total increase in fleet size 220 cars.

The 100 4k car will replaced by 100 7k cars, 192 5k cars will replaced by 192 7k cars. New total increase in fleet size 28 cars.

Total fleet size 2, 3, 6 and 7k cars 1,290.

I heard the 8k series will replace 2k and 3k. Maybe that should be a larger order of at least 500 more cars. Especially if the ultimate goal down the road is 100% 8-car operation at all times on all lines while still having spare cars in the rail yards AND accounting for cars undergoing maintenance and repair.

In my opinion the fleet size should be at bare minimum, 1,500. Your 1,790 figure would allow the folks in the shops to sustain rigorous preventive maintenance program and reduce the total number of annual miles. Replacing the 2 and 3k cars 2 for 1 would bring the fleet to 2,022. A fleet size that large would allow the above plus, with adequate power distribution system upgrades, all 8 car trains during peak at 30 trains per hour.

Sand Box John wrote:
Again it depends on who you ask and how many 8 car trains per hour you want put out on the railroad during peak.

In my opinion, no.

The origenal 7k procurement was suppose to increase the fleet size for the Silver line (128), replace the 1k cars (300), do a mid life rehabilitation to the 4k car (100), and add another (220) fleet growth to accommodate all 8 car trains during peak at 24 trains per hour. total increase in fleet size 220 cars.

The 100 4k car will replaced by 100 7k cars, 192 5k cars will replaced by 192 7k cars. New total increase in fleet size 28 cars.

Total fleet size 2, 3, 6 and 7k cars 1,290.

In my opinion the fleet size should be at bare minimum, 1,500. Your 1,790 figure would allow the folks in the shops to sustain rigorous preventive maintenance program and reduce the total number of annual miles. Replacing the 2 and 3k cars 2 for 1 would bring the fleet to 2,022. A fleet size that large would allow the above plus, with adequate power distribution system upgrades, all 8 car trains during peak at 30 trains per hour.

Seems if WMATA is serious about improving reliability and service they will need to expand the fleet big time. The 7k cars might be reliable for a while, but if they don't get the necessary preventive maintenance, Metro will eventually run into the same issues we see today with breakdowns and mechanical failures being a regular thing.

Metro might be able to temporarily expand the fleet by delaying retirement of the 5k cars. There is no safety issue forcing them into retirement (yet). If they can go through some rigorous mechanical fixes to make them more reliable, Metro might be able to stretch their life out.

I hope they can manage to make the 8k order as large as the 7k order.

"Chris Brown"

Seems if WMATA is serious about improving reliability and service they will need to expand the fleet big time. The 7k cars might be reliable for a while, but if they don't get the necessary preventive maintenance, Metro will eventually run into the same issues we see today with breakdowns and mechanical failures being a regular thing.

Metro might be able to temporarily expand the fleet by delaying retirement of the 5k cars. There is no safety issue forcing them into retirement (yet). If they can go through some rigorous mechanical fixes to make them more reliable, Metro might be able to stretch their life out.

WMATA's goal is to move away from the internal systems design of the legacy cars and go with networked internal systems design in the 7k cars. The cost of doing that was one of the reasons why the 4k cars were not midlife rehabilitated to be compatible with the 7k cars.

I hope they can manage to make the 8k order as large as the 7k order.

The reason why the fleet will have a net gain of only 28 cars when all is said and done is because Maryland did not want to pony up their share of funds to make all 8 car trains during peak possible. What Maryland needs to do is to look at the fleet, miles, boarding number of the Baltimore Metro and compare them to Metrorail to see the discrepancy.

farecard wrote: Getting the data to the trains might be an issue, but it can always use the cellular network when that is complete in ~2099

It shouldn't be an issue. The hardware is there, both carborne and wayside, to facilitate this and many other new-to-WMATA functions built in to the 7000 cars. It's known as TWDT, or train to wayside data transfer - note this is completely unrelated to TWC (train to wayside communication), a component of our ATC system. TWDT uses standard wifi, which has been installed at nearly every station at this point. Improving the passenger information displays is very, very low priority currently. There are still a substantial number of outstanding open engineering issues with the basic car design yet to work through. We've made very little progress towards implementing automatic transmission of car event and fault logs - the killer app so to speak for TWDT. If that ever becomes a reality, the next step will be rolling out automatic software updates.

Can I just say that every dcmike post is SUCH a pleasure to read.