Bueno, alors, donc, claro-- so anyway I got into this discussion on LinkedIn, which you may not be able to access for any number of reasons.
The initial point of the discussion was:
Why don't more mainline railways outside of Europe choose ERTMS when they can only achieve ETCS L2 currently and not choose CBTC where L3 capabilities are already provided?
Got that?I sure didn't and don't. But others apparently did and the discussion evolved into comparisons of ERTMS CBTC and ETCS L3. Now there is a difference among the three, with ERTMS being a protocol, a description of standards of functionality and interoperability for all railroads and suppliers participating in the ERTMS program.
ETCS Level 3 is the application of standards for train control where track occupancy and train integrity are registered and communicatedby the train itself without use of in-track vital equipment like track circuits or axle counters.
CBTC, communication based train control, may or may not achieve those standards for interoperable train control as defined by the ERTMS requirements.
CBTC is closely identified with "moving block" technologies, where safe train separation is maintained dynamically as an operating envelope around each train, and not as a fixed space separate and apart from the existence of any train.
I think that's right, but if I'm wrong, well it won't be the first time. Nor the last as I intend to live forever and fill the years with mistakes, humorous, outrageous, scandalous (but never unsafe).
The discussion, meanwhile, became one of the benefits, costs, and applicability of CBTC. At one point, a representative of Bombardier, Inc. intervened to tell us that Bombardier operates a system that is "essentially ETCS L3."
I found that to be a very interesting claim, because as far as I can tell the European Railway Agency thinks ETCS L3 exists only on paper.
So I asked our man from Bombardier how did Bombardier resolve the issue of determining the end-of-train, which of course is a critical determination for safe separation of trains.
Our man from Bombardier referred me to a paper that examined the application of a Bombardier system to a small operation in Sweden. He assured me my "doubts will be solved."
Of course, the paper states quite clearly that the determination of train integrity (end-of-train) has not been resolved for ETCS Level 3 and that on the railway where the Bombardier system is in use:
Since the lines are so lightly used (typically in the pilot line 8 passenger trains and 8
freight trains per day) and the passenger trains are single car DMUs anyway, the risk of
train separation is accepted, so the unsolved problem of train integrity proving is left for
Wait. What was that? "The risk of train separation is accepted..." That, "accepting the risk of separation" is by definition not acceptable. We recognize that the mechanisms of safe train separation may fail; the requirements may be ignored or violated; but we do not accept the risk of not having, not providing for safe train separation in our mode of operation. This "regional ETCS" is precisely not a train control system in that it does not address the vital process of the railroad.
Why do I bring this up? Is it because I dislike Bombardier? Absolutely not. I may dislike Bombardier a lot, or maybe not at all.
I bring it up because, despite the fact that I intend to live forever, I want something to be recorded for posterity. And that something is that when working in Egypt for the Egyptian National Railway, I resolved the problem of train integrity.
It was our task to devise a system for applying PTC to Egyptian train operations where blocking of trains was done, in the main, by adaptation of the British absolute block via either the Staff (token) or the Tyer (no token) method.
During that work, Ron Lindsey develop the concept of Virtual Centralized Traffic Control- V-CTC, whereby GPS information, and wireless data transmission from train locomotives, would be integrated into a graphical representation of the railway to determine occupancy and train location. Ron deserves full credit for the development and elaboration of this application.
My star in the railroad firmament hangs on the application of end-of-train devices, used by freight railroads in the US to measure and maintain brake pipe continuity, to communicate and ensure train integrity to the head end of the train and the wireless data radio system. I proposed that the telemetry signal from the rear end of the train to the head be to ON in or vital logic, our 1 in our digital world of 1s and 0s, to determine "train complete."
Integrity monitored and communicated. End of train identified and communicated. Train length known and communicated. Problem solved. Or rather half the problem solved. The other half is the other half of every solution we propose: "What do we do when the device fails?"
I'm not making a big deal of this. I haven't patented anything, and I doubt it could be patented. I don't doubt that others have thought of this, also (although I must say, when we discussed it with several suppliers, it seemed to be a new concept to them).
I just want it known that the problem can be solved, has been solved, and "regional ETCS" is not a solution.
Keep that in mind when someone tries to sell you something he or she calls CBTC or ETCS L3.
February 1, 2015
When is train control not train control?