Posts about Metro

A map at L'Enfant Plaza. North is to the right.
Photo by the author.

At the extreme south end of the station there is another mezzanine. But it does not have an exit. It's main purpose is to enable people to transfer between northbound Green or Yellow trains to southbound trains on the opposite line. It also enables patrons headed for the exit on the opposite side of the Green/Yellow tracks to cross them without transiting the lower level Blue/Orange platform.

But it is currently set up inefficiently.

Typical mezzanine arrangement. Graphic by author.

But the main reason for this design is so that riders entering the station can go directly down to the platform, while riders exiting trains encounter the up escalator first (unless they exit from one of the cars under the mezzanine). Because of this design, Metro typically arranges its side platform stations so that patrons enter and exit on whichever side of the station manager's kiosk their platform is.

This contrasts with center platform stations, where passengers usually enter and exit to the right of the kiosk (from their point of view). Although this also can vary.

Note: elevator placement varies widely because they were added to the design of the earlier stations after construction was underway.

But this is not an issue with L'Enfant's southern mezzanine. Since there's no exit, patrons don't need to be channeled to the faregates. The current setup, on the other hand, forces riders transferring between platforms to crisscross the mezzanine and cross paths with patrons moving in the opposite direction. It's an illogical, confusing setup which adds an obstacle to changing trains.

L'Enfant southern mezzanine. Graphic by author.

It would be far simpler to pair the up escalator with a down escalator in the same position on the opposite platform. This would shorten the distance patrons have to walk through the mezzanine.

Of course, on average, a person making two trips each day would walk the same distance — a shorter trip at one end of the day and a longer trip at the other end.

But it would make the mezzanine easier to navigate and give it a more logical layout.

However, scheduled maintenance has one fundamental weakness: because maintenance is based on a calendar and not the objective condition of an asset, it is almost always either too late and a breakdown has already occurred, or it is way too early and thus wasteful. The breakdowns, of course, only increase reactive maintenance expenses, thus undermining the attempt to be proactive and stealing funds from proactive maintenance efforts.

The FTA is even complaining that manufacturers are building vehicles whose maximum useful life is based on agency expectations. While this weakness can be partially addressed by scheduling maintenance based on usage and not a calendar (just like a car's 3,000 mile maintenance intervals), any scheduled maintenance strategy inevitably creates a false costs vs quality trade-off. This is because the only way to improve reliability through scheduled maintenance is to increase its frequency, which further increases wasteful maintenance costs.

Much of the nation's built environment was built in the same generation as MetroRail, and our daily lives have become increasingly dependent on this infrastructure. Maintenance of aging infrastructure is thus not just a MetroRail challenge but one of the leading challenges facing the country. Scheduled maintenance could bankrupt our country while still leaving it with an unreliable infrastructure. Fortunately, maintenance best practices have developed that provide a blueprint to a smarter, leaner and more reliable built infrastructure.

Reliability-Centered Maintenance: Reliability-Centered Maintenance initiates maintenance activities when monitors or tests indicate that an asset's condition is likely to lead to breakdown. For example, vibration or temperature, two of the most common leading indicators of breakdowns, are easily monitored with remote sensors. Because the condition of an asset, instead of a schedule, determines when maintenance is initiated, this approach is called condition-based or reliability-centered maintenance.

The goal of reliability-centered maintenance is to initiate the right maintenance at the right time. The result is that maintenance is less costly and more effective.

DoD Hierarchy of Maintenance Approaches

Identifying the conditions that are leading indicators of different types of breakdown is accomplished through Failure Modes and Effects Analysis (FMEA). The ways in which a car or bus system or subsystem could fail, its failure modes, are identified along with the possible causes of each failure mode. Causes of failure modes that are more likely to occur or have severe consequences are then monitored using remote sensors or manual tests. FMEA is an essential step to improving both reliability and safety at Metro.

Where is Metro on the hierarchy of maintenance approaches? Metro currently practices calendar-based scheduled maintenance, and has made the decision to migrate to usage-based scheduled maintenance. While this is good, it will not enable Metro to return to its glory days at an affordable price. The prospect of migrating to reliability-centered maintenance has both good and bad news.

The Good News: Many pieces are in place for a transition to reliability-centered maintenance that would be a model for the nation's transit agencies.

First, WMATA has invested in the leading asset management software system (IBM Maximo) which supports reliability-centered maintenance. Metro is currently using Maximo to track every asset it owns (267,000 assets) so that, for example, replacement components can be identified instantly or maintenance instructions can be remotely downloaded for any component. The Safety Management System that was quickly built by WMATA IT this year enables the Safety Office to analyze failures through point-and-click identification of components in any system.

However, Maximo could also be used to associate asset conditions (e.g. temperature levels) with failure modes. When this is done, Maximo can not only enable more cost-efficient reliability-centered maintenance, it can even use the data it collects to report the maintenance or replacement costs required to support any asset availability target (e.g. 99% availability). Imagine a capital expense budget that includes this type of data-driven, performance-based justification for each line item.

Second, WMATA has equipped the majority of its buses with Automatic Vehicle Monitoring (AVM) instruments. These instruments continuously survey the bus during operation, silently collecting fault, performance, and service data from braking, electrical, engine, transmission, security, fare collection, accessibility, and climate control systems, and then automatically uploading the data nightly.

The Bad News: Despite the presence of the building blocks for implementing maintenance best practices, there seems to be no management-level leadership in maintenance best practices, perhaps the most critical discipline for the future of Metro. As a result, WMATA remains in the trap of expensive reactive maintenance caused by calendar-based maintenance schedules that are independent of the conditions of WMATA's 267,000 assets.

A case in point is the elevators and escalators, some of whose manufacturers are out-of-business requiring expensive consultants or wholesale replacement. However, we were only reliant on these manufacturers because we implemented their maintenance schedules, instead of conducting Failure Mode and Effects Analysis to develop our own internal knowledge base and condition-based maintenance system for each elevator and escalator. Now Metro has hired a consultant to "fix" the elevators and escalators in 4 stations, a short-term reactive solution that will only work until the next elevator or escalator failure in those stations requires another heroic, expensive consultant.

WMATA can do this. It's been done in the airline and defense industries, and it will eventually be done in transit. The WMATA Board should select a GM with experience in reliability-centered maintenance, preferably from the airline or defense sectors. And we should encourage WMATA to lead the way among transit agencies, none of whom have adopted these maintenance best practices, lest rail travel across the country be increasingly perceived as out-dated, dangerous and unreliable.

L'Enfant Plaza has the most escalators of any station in the system &mdash 31. Gallery Place comes in a close second with 30 and is followed by Metro Center's 25.

On the opposite end of the spectrum, Forest Glen, the deepest station in the system, has no escalators. The only way for patrons to get to the surface is by elevator. Twinbrook has just 1 escalator and there are 11 stations with only two escalators.

The fact that the downtown transfer stations have scores of escalators is no surprise. But the fact that Union Station, which is one of the busiest stations in the system, has less than one-third as many escalators as Gallery Place or L'Enfant Plaza is interesting.

Some stations, like Woodley Park, have higher numbers because they have two-stage exit escalators.

Of course, as upkeep problems have mounted, there have been calls to replace some escalators with stairs. While stairs can't move as many people per minute as an escalator, they also don't break or have to be closed for repairs very often.

A 2006 study by Metro looked at converting 23 escalators to stairs. It noted that the annual upkeep cost of a Metro escalator is $51,000.

Metro doesn't seem to have moved on that particular study. But even if they had, the sheer volume of escalators in the system means that we're going to have a lot of them for a long time to come. Increasing their reliability needs to be near the top of Metro's priority list.