I am sure OPB will weigh in on the merits of PTC, but we should not be putting all our eggs in one basket. The fact of the matter is, that while PTC will improve safety, it will not by any means eliminate catastrophic collisions. Putting a computer in control is only as safe as the software and electronics behind the system. Take the WMATA incident which OPB referred to. The system the were using was supposedly failsafe, meaning these collisions were supposed to be "eliminated". However, due to an engineering flaw in the system, one of the trains was not detected by the computer and a route was cleared, causing the accident. This flaw (the vendor would claim otherwise) boils down to an electromagnetic compatibility issue, something which can be mitigated but is very difficult, expensive and often impossible to attenuate completly - especially in an environment which must be failsafe.

Being an electrical engineer, I am very technologically centered. But I will be the first to state that blind reliance on technology is not wise. By requireing compliance to crash compliance standards, coupled with improved control technology, the risk of catastrophic accidents is reduced signifigantly. So when the very seldom accident does occur, its effects are minimized. This is the benefit of heavier equipment, that the electronics are not the fix-all solution we might think it is.