[jandrese]

This was my thought. Floppy emulators are a dime a dozen thanks to the retrocomputing community. Emulators for the custom boards full of discrete logic, opaque ROM chips, PLAs, and so on from long dead companies are going to be a much bigger challenge.

If they had good schematics for all of the parts it might be possible to keep the the system running for a long time with a couple of smart EEs who are comfortable with the scope and soldering iron, but eventually they're going to run out of some obscure part and be up a creek.

Or maybe they could replace entire boards with home designed versions condense all of the old logic down to one chip and a handful of support components and start in-place upgrading without a total system revamp. Still an expensive process, and one that requires some hard to find engineers on staff, but theoretically spreads out the upgrade process over many years. It also loses out on functional improvement opportunities while your system is made up of a hodgepodge of old and new hardware.

[inferiorhuman]

SelTrac was designed to use commercial off the shelf (COTS) parts so there shouldn't be much in terms of needing custom chips, etc. The problem is that Alcatel (now Thales) basically doesn't support any of this (and hasn't for a long time).

The computers in question are, I believe, just thin clients.

[asdefghyk]

RE "....Still an expensive process, ....." Actually probably NOT , if all the $$ saved over the last 25 years , and also considering the many millions to get a completely new replacement system....

[jandrese]

The expense will be in "certifying" the machines for use with passenger traffic. Nobody wants personal liability, so we wrap ourselves in knots trying to pass responsibility on to someone, anybody, else.