Positive Train Control: Why it’s Taking So Long to Get Rail Safety On-Track

Positive Train Control

by Matt Burns, PE

If positive train control for rail safety is important, what’s taking so long?

Positive train control (PTC) is an important life-safety technology that helps prevent human error in passenger and freight train operations. Understandably, there is frustration when loss of life could have been prevented if only safety systems were in place. For all the promise PTC holds in crash prevention, why has it taken so long to implement?

The benefits of automated train control and PTC have been known for some time. PTC was mandated by Congress in 2008 after numerous fatal train crashes pulled the issue of safety to the forefront. The mandate stated that PTC was to be installed and operational by Dec 31, 2015. Few railroads were able to meet this deadline, and some were nearly forced to cease operations for non-compliance. Reluctantly, Congress granted a 3-year extension and 2-year grace period for those agencies demonstrating progress, effectively extending the deadline to 2020.

As PTC systems are being installed around the country, some common themes are emerging that help us anticipate the challenges facing the installation of this new technology. Our experience with the complex rail systems in Philadelphia, St. Louis, Alaska, and recently, Boston, point to some common hurdles facing the rail industry in the PTC implementation process.

  • PTC implementation is expensive, and fundamentally remains an unfunded mandate for cash-strapped public transit agencies.
  • Signal systems touch nearly every aspect of an operating railroad system. Legacy systems, systems that are over 50 years old, add another layer of complication to the PTC implementation process.
  • “Dark territory”, areas without signal systems, require new infrastructure to adequately support the demands of PTC.
  • Testing and integration of a completed system is time consuming, and involves close coordination among stakeholders and the Federal Railroad Administration (FRA).
  • Demand is high for the limited radio frequency spectrum needed for a digital radio system. Necessary antenna structure requires FCC approval, and can be subject to land-use regulatory delay.
  • There are few equipment vendors that supply PTC components, and the non-competitive environment drives up cost and lowers availability, putting PTC suppliers in the driver’s seat.
  • Retrofitting locomotives and cab cars requires custom solutions because off-the-shelf products have not proven to be easily adaptable.

These challenges have significant impact on rail systems looking to comply with the PTC mandate, and create cost and schedule uncertainty when procuring, installing and validating a system. PTC and rail signal systems are sometimes viewed by skeptical rail operators as mysterious black boxes requiring unending time and capital resources to install.

Here are a few observations on how these challenges can be understood and tackled:

Expense: The estimated price tag for PTC on 20 commuter railroads is $2.75B for the initial hardware installation. So far, Congress has only appropriated $50M, so agencies need to plan a portion of their limited capital be allocated to PTC over time. There is also an ongoing cost of technology for updates to software define radio (SDR) systems. SDR provides a continuous path for interoperability, as radios can be reprogramed and reconfigured on the fly. Railroads need to budget ongoing licensing fees for software updates and IT support, much like any business computer operating system.

Integration: Legacy signal systems do not integrate easily with PTC. Additionally, the two dominant technologies, ACSES (Advanced Civil Speed Enforcement System) and I-ETMS (Interoperable Electronic Train Management System), function much like the iPhone and Android cell phones and their respective operating systems. In some cases, both ACSES and I-ETMS systems are needed for interoperability. Rail organizations need an in-house champion to help PTC installation overcome internal obstacles and decision-making challenges, and to open doors when it’s time for field testing.

Testing & Validation: It is critical to field test a system in order to validate it for operation and get it approved by the FRA. While lab testing takes less time, validation in actual field conditions is required. Scheduling service outages for adequate and productive testing during off-peak time slots can be tricky. The most effective testing strategies select a rail line segment for early prototyping, and use the results of this smaller sample to improve productivity during valuable track outage times.

Radio Spectrum & Antennas: It is important to acquire radio spectrum for the PTC communication system early in the process so that band allocation can be achieved at a reasonable cost. The FCC continues to narrow bandwidth and channel spacing, creating needed channels for railroads. New radios have to be very narrowband (NXDN) compatible, and large passive filters may be needed to attenuate interference from closely spaced channels. Along the wayside antenna structures usually require FCC approval. Regulatory approvals have slowed due in part to some antenna sites containing Native American burial grounds.

Suppliers: Manufacturers are struggling to produce the equipment in the quantities necessary to meet the FRA’s mandated deadlines. There are long lead times for proprietary products, and orders need to be placed in advance to reserve a production commitment. Smaller projects face challenges as manufacturers may not have interest in producing limited quantities.

Retrofits: Placing new radio equipment in locomotives and existing wayside signal enclosures has been challenging due to space constraints and interoperability requirements. In some cases, two systems are needed to cover different system vendor protocols. Large passive filter devices are sometimes needed on-board for certain radio band operations, requiring additional physical space in already tight quarters.

PTC is an investment and long-term commitment to safety. A well-planned, deliberate approach to PTC implementation, including careful anticipation of challenges and consideration of lessons learned, will reduce uncertainty around cost and schedule.

Most importantly, PTC can save lives. We want to help you keep your promise to deliver this important rail safety technology to the traveling public.