Urban population densities are increasing and transit operators are demanding more from their transit infrastructure to reduce headways and increase throughput.
Unfortunately, technology and signalling philosophies developed in the 19th and 20th centuries are not meeting that challenge.
As a result, rail automation is gaining steam. Over the past 30 years, transit operators are shifting to semi or fully automated signalling systems.
The benefits of automation are clear: reduce human error, increase safety, reduce maintenance and increase operational performance but, this comes with a cost in terms of complexity and price tag.
Therefore, how does a transit operator decide how much automation is enough automation for their property?
Experienced CBTC Transit Operators keep a laser focus on their diagnostic design because the time it takes for the Operator to identify a problem, localize the problem and fix it is determined by the diagnostics capabilities of the CBTC solution.
Sophisticated diagnostics enable the Operator to recovery from failure quickly whereas rudimentary diagnostics delay recovery while commuters are stuck on the track.
Given that all railroad properties are under constant maintenance, creating a safe corridor for workers at track level, while maintaining service through the work zone is a critical concern for Operators.
In a CBTC application, work zones take on greater importance because the trains are either driverless or operating in an automated mode with a train Operator. If a CBTC train enters an area with workers, the train will not stop; it will continue to move at the same speed. There must be a vital mechanism to inform the CBTC system of workers at track level.
Operationally critical functions must be understood when deploying a CBTC solution. These functions define how a railroad operates once the solution is deployed and if neglected the Operator can expect service disruptions, longer recovery times and irate commuters. Laser-focus on the CBTC solution’s operational functions will ensure that the operational requirements of the Operator are satisfied.
Fallback mode in a CBTC application, is a legitimate mode of operation but avoid it when possible. The cost of implementing a fallback mode will outweigh the marginal benefits that fallback will provide: increased complexity, increased maintenance cost and up to 30% increase in capital costs. Yet some operators handcuff their solution by imposing a fallback mode requirement without understanding the need.
The operating environment ultimately determines if fallback mode is required and which of the multiple options is selected. The operator must take a methodical approach when evaluating the need for fallback because the consequence of making the wrong decision are costly.
When some transit agencies being down the path of deploying a CBTC solution, they assume their engineers understand their operational requirements and begin writing a technical specification.
This assumption is wrong.
Frontline personnel (such as train driver or maintenance personnel) understand the daily operational needs of the Transit Agency because they operate the system day in and day out
From a CBTC perspective, a ConOps is written with the end-user in mind and it describes what the transit agency expects from the CBTC system.
The ConOps is concerned with the operating environment where the CBTC system will reside in and where frontline personnel work to deliver service.
The CBTC system must address the needs of these frontline personnel and the purpose of the ConOps is to capture the needs of these workers.
