Good afternoon, I am wondering how much of ACSES (Advanced Civil Speed Enforcement System), the Positive Train Control used on the Northeast Corridor was implemented in the NEC: NY route. For those who are unaware, ACSES is an extremely complex PTC solution. Some of its most prominent features are: Enforcing positive stop at interlocking home signals. This means that if the home signal at an interlocking is a STOP signal, the on-board ACSES apparatus will ensure the train comes to a complete stop before the signal. The train will usually stop within 1,000 feet of the signal. This is enforced via ACSES transponder sets place in the track gauge just before the home signals. Enforcing Temporary Speed Restrictions (TSR). The dispatcher can implement TSR's for certain areas in real-time. The on-board ACSES apparatus can receive and enforce these speed restrictions. Calculating a maximum safe braking curve. The on-board ACSES apparatus knows how far the train is at all times from upcoming speed restrictions. It is also aware of the current speed of the train. With these two pieces of information in mind, it is constantly calculating a safe braking curve for upcoming speed restrictions. Once the train gets close to exceeding this braking curve (also known as the "Alert Curve"), the Aspect Display Unit (ADU) will start gradually lowering the Maximum Authorized Speed and force the engineer to apply brakes and acknowledge the speed reduction. If the engineer does not acknowledge in time, an ACSES brake penalty is applied. This automatic braking curve calculation isn't meant to replace the engineer's knowledge of the physical characteristics of the area and is only in place to ensure the train complies with Permanent Speed Restrictions. Here is a graphical representation of the braking curve, courtesy of Siemens Inc. Here is a photo of the Aspect Display Unit, also courtesy of Siemens Inc. You'll see this in the ACS-64 cab when operating in NEC: New York! The numerals underneath "Maximum Authorized Speed" (MAS) will always display the maximum authorized speed for your specific train (in miles per hour). Since the ACS-64 with Amfleet I coaches is an ACSES Type "B" consist, Type "B" speeds will be enforced. There are different train types (A through E) on the Northeast Corridor (except between New Haven and New York). ACSES will enforce these varying speed limits based on the train consist. As stated before with the braking curve, the numerals underneath MAS will start to decrease in value when the "Alert Curve" has been reached. For example, you are in 60MPH territory and there is a 40MPH curve ahead. Once the "Alert Curve" has been reached (as calculated by the on-board ACSES apparatus), the numerals in MAS will start to decrease from 60. It could show 59, then 57 a couple seconds later, 55 a couple seconds after that, etc. Once the alert curve has been reached, the engineer must control the train accordingly in order to avoid an ACSES penalty. Now for a real-world example. There's an awesome video on YouTube titled "SEPTA Fox Chase Line ACSES (PTC) Tutorial Northbound" which illustrates the braking curve functionality perfectly. NOTE: SEPTA uses a different version of the Aspect Display Unit, but the functionality is similar. A trainee engineer was at the controls. At 4:25, the train is in an area where the MAS is 50MPH. The train is traveling 42MPH. There is a 30MPH restriction ahead. the ACSES apparatus is aware of this but is the trainee engineer aware? At 4:31, the ACSES Alert Curve takes effect. This is known because the numerals beneath "Maximum Authorized Speed" start to decrement from 50 (the MAS in the area). At this point, the engineer has to ensure he brakes in such a way that his actual speed doesn't go above the maximum authorized speed for a prolonged period of time. If it does, an ACSES braking penalty will apply. So back to my question. Was any ACSES functionality programmed into the NEC: NY route? Thanks and let me know if you have any questions, Brandon Want more information about ACSES? Siemens has an excellent article. https://w3.usa.siemens.com/mobility/us/en/Events/railway-interchange/Documents/SIE_BRO_ACSES.pdf This video is a bit corny, but is pretty accurate. Feature differences between Cab Signal System (CSS), Automatic Train Control (ATC), and Advanced Civil Speed Enforcement System (ACSES).