Renovation of underground PATCO stations

I know I posted this query before, but I don't think I worded it quite correctly: When did PATCO start going through and renovating their underground station platforms, between City Hill Camden and 15th-16th Locust? Surely some point in the mid-90s? I read here that in 1998, PATCO become the first ADA-compliant transit system in the country...
http://www.trainweb.org/phillynrhs/patco.html" onclick="window.open(this.href);return false;
So maybe they were done by then?

Well the line isn't 100% ADA compliant because not all of the stations have elevators and the cars are undergoing a rebuild program (the rebuilds are ADA compliant). Plus, that site needs to be updated because it is now 2017 and Franklin Square has not reopened.

That's very interesting, but my curiosity is geared towards the paneling and floor tiles in stations such as 15th-16th, 8th-Market, and other underground station - except Broadway.