Obviously the price tag for the NY system is crazy, but honestly so is what you guys are proposing... It's almost completely impossible to certify a safety crit

Obviously the price tag for the NY system is crazy, but honestly so is what you guys are proposing... It's almost completely impossible to certify a safety critical system with WiFi and Arduino/RPi. This kind of engineering is a whole different ball game, and for good reason (train crashes and derailments are really not pretty). For an informational system (i.e. telling passengers how long trains are away or for statistics gathering), sure. You could absolutely do that like you say. But as soon as it involves controlling the train or anything to do with signalling, it just can't be done like that.