Gets kinda confusing with all the different types of PTC in existance.
Per https://railroads.dot.gov/train-control ... nformation
Types of PTC Systems in the United States
ACSES (Advanced Civil Speed Enforcement System): A transponder-based system, in use on Amtrak's Northeast Corridor originally put into use on the Northeast Corridor by the specific requirements of an Order of Particular Applicability. (Type Approved and Certified by FRA.)
ACSES II: The latest version of Advanced Civil Speed Enforcement System, and acts as a vital overlay to an Automatic Train Control (ATC) system comprised of a Cab Signaling System (CSS) and a Speed Control System (SCS)
. (Type Approved and Certified by FRA.)
Both of the above favored by Amtrak on the NEC.
CBTC (Communications-Based Train Control): A vital stand-alone Positive Train Control (PTC) system, as defined in 49 Code of Federal Regulations (CFR) Part 236, Subpart I, Section 236.1015(e)(3). CBTC replaces the existing traffic control method of operation by requesting an override of the wayside signal system to display a Flashing Green or Flashing Yellow (if the green aspect does not illuminate) signal aspect. (Type Approved and Certified by FRA.)
Favored by autonomous metro and light rail systems
I-ETMS (formerly called Vital Electronic Train Management System): A GPS- and communications-based system ready for deployment. It is the system of choice for CSX Transportation, Norfolk Southern Railway, Union Pacific Railroad and BNSF Railway. Various passenger/commuter and other railroads are adopting it for compatibility and interoperability. (Type Approved by FRA.)
Wabtec’s PTC just about everybody apparently is implementing. The on-board computer, with the aid of an on-board geographic track database database and GPS system, constantly calculates warning and braking curves based on all relevant train and track information including speed, location, movement authority, speed restrictions, work zones, and consist restrictions. I-ETMS also queries wayside devices, checking for broken rails, proper switch alignment and signal aspects. Apparently the computer's monitors can act much like cab signaling.
ITCS (Incremental Train Control System): A GPS- and communications-based system used by Amtrak on its Michigan line, authorized for passenger train speeds up to 110 mph, originally put into use by the specific requirements of an FRA-approved waiver. ITCS certification through Amtrak's request for expedited certification process is pending successful resolution of a few remaining issues prior to FRA approval for certification.
Maybe a dud?
E-ATC (Enhanced Automatic Train Control): A system that uses an underlying automatic train control (ATC) system, in conjunction with other “enhanced” features or systems to achieve the core required functionalities of PTC. These systems are often integrated with underlying cab signal systems (CSS) and centralized traffic control (CTC) systems
, in addition to other signal or train control system enhancements the railroad elects to make, to meet the full requirements of PTC.
CapMetro in Austin and DCTA in Denton chose this, the Stadler GTWs max speeds is just 75 mph. Cab signaling debate for higher speeds not applicable.
I-ITCS (Interoperable Incremental Train Control System): A safety-critical, overlay system as defined in 49 CFR Part 236, Subpart I, Section 236.10 15(e), to be used in conjunction with the existing method of operation (Traffic Control System). I-ITCS interoperability is achieved by incorporating the same capabilities as the Interoperable Electronic Train Management System (I-ETMS). (Type Approved by FRA.)
Caltrain plans to use this, interoperable with I-ETMS. CHSR will reach speeds of 110 mph, and Caltrain's Stadler KISS trains max speeds is 110 mph, but Caltrain plans to operate at a maximum of just 79 mph.
SafeNet System: The Argenia Railway Technologies’ Positive Train Control (PTC) system (SafeNet System) is a non-vital overlay PTC system, as defined in 49 CFR § 236.1015 (e)(1). The SafeNet System will be used in conjunction with the existing method of operation, centralized traffic control (CTC), which interfaces with existing signal systems, wayside devices, and office train dispatching systems Computer-Aided Dispatch (CAD) via multiple communications links. (Type Approved by FRA.)
Nashville & Eastern Railroad Corp. choose this, a moving block computer solution. Nashville's Music City Star commuter rail runs on their tracks. Commuter rail operations, no need to go faster than 79 mph, so cab signaling for higher speeds is not applicable.
Sentinel System: An overlay Positive Train Control (PTC) system, as defined in Title 49 Code of Federal Regulations (CFR) Part 236, Subpart I, Section 236.l 015( e )(1 )(ii). This CBTC system is overlaid on the existing method of operation and provides enforcement of movement authority limits, maximum authorized speeds, permanent and temporary speed restrictions, and incursion into roadway work zones by a positive stop. (Type Approved and Certified by FRA.)
North Shore Railroad, another commuter railroad, was planning on using this, and is not a stand alone system. As a commuter railroad, chances they will be going faster than 79 mph is unlikely.
So, some PTC systems will still require existing cab signals, some will provide an equivalent of cab signals on a computer monitor/display, and some probably will not just providing an auto stop, and others set up moving block system. It is a toss up depending upon what they choose to use.