How should the MTA update its signal technology?

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How should the MTA update its signal technology?

Gov. Andrew Cuomo and subways chief Andy Byford are at odds over how to update subway signals. They both might be right.
April 24, 2019

Gov. Andrew Cuomo has never been known to take a back seat on important issues at the Metropolitan Transportation Authority, but his latest clash with New York City Transit President Andy Byford gets into the nitty-gritty of what technology should be used to update the subway’s signals system.

Cuomo and Byford have disagreed publicly about whether the MTA’s signal repairs should use communications-based train control – technology Byford favors because it’s been proven successful, but which Cuomo mocks as archaic – or ultra-wideband radio – a technology Cuomo backs that could shorten the timeline for repairs, but which has never been used by a major transit system. The disagreement represents a larger criticism that Cuomo has made of the MTA before, which is that the authority is stagnant and closed-minded to innovation, on issues including the L train shutdown.

In this week’s “Ask the Experts” feature, we got to the bottom of which technology is better, and whether Cuomo’s approach on these issues is the right one. We asked four experts to weigh in: Jonathan English, a doctoral candidate in urban planning at Columbia University; Hany Elgala, an assistant professor of electrical and computer engineering at the University at Albany; Ben Kabak, editor of the transit blog Second Ave. Sagas; and Robert Paaswell, director of the University Transportation Research Center and former executive director of the Chicago Transit Authority. Responses have been lightly edited for clarity.

Should the Metropolitan Transportation Authority use ultra-wideband radio or communications-based train control?

Jonathan English: One of the most serious problems facing the city today is the decreasing reliability of the subway, and its antiquated signalling system is an important part of the problem. The MTA has been looking at communications-based train control (CBTC), which will allow much more precise knowledge of exactly where trains are in the system. CBTC is a proven technology that has been developed over decades and successfully implemented around the world. The MTA, and New York City more broadly, have struggled badly in recent years to successfully deliver important infrastructure projects. It’s a very risky idea for this city to pioneer a brand new, unproven technology on an application as critical as subway signalling. People often complain that technological progress in things like transportation is so slow when their iPhone software gets upgraded every few months. The difference is that when a phone app crashes, it’s annoying. When a signalling system fails, people die. The standards required in life-safety-critical applications mean that new technologies can’t simply be implemented with problems fixed along the way.

Ben Kabak: The two are not mutually exclusive, and the MTA should be assessing all potential technologies. In this instance, ultra-wideband radio is the telecom backbone that would provide some of the communications infrastructure for CBTC. It’s a new but untested solution, and it’s not clear if the MTA can get UWB radio signals to work reliably in very old subway tunnels which have posed problems for radio-based communications systems in the past. I prefer to think of it this way: Should the MTA delay CBTC installation to adequately test and assess ultra-wideband communications? To this, I say no. The MTA can move forward with the tried-and-true CBTC technology in place throughout the world while also looking for ways to innovate so that installation can be quicker and costs lower. To that end, exploring UWB is a worthwhile venture.

Hany Elgala: It is not accurate to compare ultra-wideband (UWB) radio with communications-based train control. Otherwise, we are comparing apples and oranges. Ultra-wideband is a wireless technology that uses the radio frequency range of the electromagnetic spectrum and is a standardized technology. Communications-based train control is a whole system that makes use of wireless technologies to fulfill the mission of traffic management. Different CBTC systems from different vendors have different architecture and rely on different wireless enabled hardware equipment mounted on the track, on-board and along the wayside. Managing the traffic in a more efficient and safe way mainly relies on a high-resolution and reliable train location. Compared with proprietary radio-based, WiFi or LTE CBTC solutions, the UWB is a potential candidate to offer simultaneous bi-directional wireless communication, localization and ranging functionalities. I believe that the MTA should pursue with the UWB as a wireless technology option and explore the challenges CBTC systems pose to proprietary radio-based, WiFi or LTE networks with regards to range, mobility, radio resource access, quality of service and interference. A traffic management system based on hybrid wireless technologies is a valid option.

Robert Paaswell: Ultra wideband is a good technology, emerging for use in transportation systems. Data rich, if properly applied, it can give precise info on train locations as well as other data particular to the train. CBTC has been tried for many years, it works, crews are trained and it would be a successful application; however, ultra-wideband is the eventual technology that can modernize the fleet. The initial cost is more testing, and bringing on board data specialists – or training current computer savvy electrical and track workers – to maximize the application of UW. An analogy is going from swipe card fare payment to mobile ticketing without an intermediate fare card.

What do you think the MTA will do?

Robert Paaswell: I think they will do a big test of UWB; CBTC is only on the L and 7 lines – and has taken too long to roll out to other lines. UWB should be installed and tested on congested lines like the 4, 5, 6. A real cost-benefit should be done, assessing not only the cost of purchasing – or contracting for – UWB but the real-time ability to manage the fleet for greater capacity and reliability. Benefits include rider savings, maintenance costs and information returned for better fleet management.

Ben Kabak: The MTA is under pressure from the governor to both adapt new technologies and improve service by speeding up CBTC installation. The agency will likely keep up its current trajectory: ongoing tests of the ultra-wideband radio communications and a push to speed up the rollout of CBTC system-wide per Andy Byford’s plan. Hopefully, the MTA will have enough leeway with the governor to independently assess whether UWB is viable. What I don’t want to see happen is the governor ram through a push to use UWB if it’s not going to work reliably enough to power CBTC.

Jonathan English: Byford’s proposal has been to implement the proven CBTC technology as quickly as possible on overcrowded corridors like Lexington, while piloting the new technology in a relatively low-complexity environment like the Times Square-Grand Central Shuttle. Signalling is incredibly complex and it will take years to work out the problems with an untested technology. If ultra-wideband does make sense for signalling, that’s the best way to figure it out.

Hany Elgala: The MTA will continue exploring UWB as a complementary wireless technology and not an alternative to other proprietary radio-based, WiFi or LTE technologies. I think that the goal of the MTA will be the evaluation of a CBTC system aided by UWB to simplify the installation, reduce the installation, operation and maintenance costs and most importantly the support of multiple applications rather than a single traffic management application. Other safety applications could be the detection of objects obscuring the tracks and tracking of workers near the right-of-way.

On issues like this, what do you think of Gov. Andrew Cuomo’s approach?

Hany Elgala: It is an opportunity to have a governor that supports the authority to adopt promising technologies that can save costs, can prevent the MTA from being burdened by conventional CBTC systems and can enable offering of new services and applications. From a technical point of view, I think that Cuomo’s advocacy for UWB is considered a support for the MTA to be open-minded and evaluate state-of-the-art solutions to better serve the millions of residents and visitors of New York City. Scientific basis and engineering approaches, of course, are major factors to be considered when making the final decision.

Ben Kabak: It’s a positive that Cuomo is using his role as the state official in charge of and responsible for the MTA to push for a reassessment of how the MTA approaches technology. Someone had to come along to shake things up. I worry that his scope and frame of reference is too limited. Why, for example, is he relying on open-call contests – the origin of the UWB proposal – or the same pair of professors from Columbia and Cornell when the world is his oyster? New York City’s peer cities are light-years ahead of the MTA when it comes to technological adaptation, and these cities and their officials would be happy to provide advice or expertise to New York. Instead of looking only within his sphere of core supporters, Cuomo should push the MTA to explore international collaboration with transit agencies engaged in best practices around the world.

Robert Paaswell: His approach is to use the best expertise available. This should be a combination of in-house operations managers who have much familiarity with rapidly emerging transit technology – for buses as well as rail – and external peers. They can come from other modern properties – most in Europe or Asia, but also LA and Chicago – the railroad industry, the airline industry and the computer industry. Peer assessment and review is commonly done for European and Asian large capital projects and should be a standard approach for the MTA.

Jonathan English: It’s fair for Cuomo to press the MTA to consider ideas from outsiders. Transit agencies tend to be conservative – often for good reason – and sometimes need a push to consider different ways of doing things. But new ideas aren’t always the right ones, and repeatedly overriding the expert advice of the people he has put in charge of the MTA, including someone with as much experience as Byford, is not the way to run a railroad.

Annie McDonough
is a tech and policy reporter at City & State.
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