BandA wrote:Is there a published specification for this "ASA computer" and the train signal cabling?
Not really. Train control cabling is rote-generic and heavily regulated by the FRA for universal compatibility. You've got the air brake cable like any freight or passenger train would have, the HEP electricity cable for any passenger train, and data cables for essential systems in each coach (remote door controls, PA speakers, conductor radios at the control panels, electric signal for turning on/off the right set of marker lights on the rear car/loco running at the terminating end of the cable, etc.). For push-pull trains only that data cable doubles as the pipe for passing the train signaling one-way from cab to loco through all cars in-between when running in push mode. It's 'dumb' by design, as something that simple that works on pass-thru ensures near-universal compatibility and easy troubleshooting of the most mission-critical interconnections.
That's pretty much it...same general near- universally compatible setup everywhere ever since the 'modern' push-pull era was perfected in the first 5-10 years after the end of steam. Any car--freight, passenger, or dead-tow FRA-compliant DMU/EMU--are by-law universally compatible on brake signal. Any loco equipped with HEP output (excludes most freight) can provide electric power to 90% of the continent's coaches except for a couple outlier systems with a voltage difference (Canada: VIA Rail, GO Transit, and ???). The vast majority of coaches can work the same pass-thru data for PA/comm and doors just fine, which is why hererogeneous fleets and leasers are no impediment to most commuter rail systems. And cab cars are more often than not compatible, although national fragmentation in signaling & PTC limits their portability by region and leaves lots of little asterisks.
The ASA computer takes advantage of what's already there. Audio is just the regular PA signal as if a conductor or engineer were speaking, and the monochrome dot matrix LED's are so extremely low-bandwidth they just slip a few digital bits through what's already there. That's how every untouched old coach is able to take the ASA audio, and how the display signal can pass through a bunch of old cars to show info on any of the bi-level screens. Putting the source computer in the cab car is simply so it doesn't require a duplicate computer installation in the loco for pull mode, and so leaser locos (which are more frequently borrowed than leaser cabs) can work in the mix. With all this talk of firmware glitches in this thread, you can easily see what a cluster that would be to have completely different ASA sources outbound vs. inbound--loco vs. cab--each with their own potential set of bugs. Most commuter rail agencies prefer that cab car- only ASA setup as a result. Amtrak, being a majority pull-only system with only a handful of P-P corridor routes requiring a proportionately tiny systemwide cab fleet, would probably prefer having its ASA live in the loco-only if it opted to implement its own system.
The only custom element the T (or anyone else) orders is the computer itself, and they custom-program it for whatever tasks they want it to do. But that's not "nonstandard" any more than every transit agency hires a different Wi-fi vendor selling a different in-coach Wi-fi system. It's all 95% software meant to be constantly changed, upgraded, and meshed with other technologies. T and/or Rotem may have chosen poorly on this particular ASA setup, but it isn't a strike against them on over-noodling with unproven car design
specs like the complete Rotem and HSP-46 physical builds were.
Any modern coaches/cabs built in last 20 years no doubt have all-digital fiber data cable replacing or augmenting the copper cabling on the 'dumb' pass-thru data connection, and 4-year major inspections quickly overchurn legacy fleets with similar cabling upgrades since it's cheap and easy to install. New fiber generally isn't needed for something as dirt-basic as passing thru the ASA info, but it enables future enhancements like faster Wi-fi chained throughout the consist instead of isolated in each individual car's hotspot, higher-bandwidth info screens (scrolling ads, hi-res info boards like you get at subway stations now), and even in-seat entertainment like the airlines do on an Acela or old Amfleet first-class car when Amtrak gets its trackside ultra-high bandwidth Wi-fi installed across the NEC. I'm sure all the Rotems and 900-series K-cars came factory-built with high-bandwidth fiber since it's S.O.P. for any modern build, and that the 700's are getting fiber now as their cabling gets renewed. Next procurement displacing the Bombardier flats will probably overchurn whatever cars are left that don't have any high-bandwidth data transmission.
And then it's just a matter of the T (or any other agency with a newish fleet) brainstorming ways to take advantage of all that onboard fiber bandwidth. Same way experimenting around gradually introduced new data frills to subway stations after all that trackside fiber was laid 15 years ago for the Charlie/AFC rollout; it's got nearly inexhaustible bandwidth for piling on new things. Probably will see it first manifest itself onboard the CR fleet with inevitable security-cam installs on the coaches once they get a Homeland Security grant to bring Big Brother aboard for some live remote monitoring.