when something needs to run day-in and day-out every day, it is difficult to justify swapping things just because they're old.

as it turns out, old things have stood the test of time and generally work quite well.

vancouver bc upgraded its own train control systems a handful of years ago. unsurprising to anyone who has tried to do a migration, there were service incidents. trains stuck in the middle of nowhere sort of thing.

It's all done, upgraded, and modernized yet. But there is a growing pain and growing cost. The tricky thing to know is when the juice is worth the squeeze.