[iDemonix]

If the timetables aren't particularly easy to read or parse, OCR is going to be potentially wrong so you're going to have to check it, so you might as well do it manually whilst there's no clean technical way of doing it (maybe contact the companies if you get big numbers and ask about an arrangement?). You could setup a script, on a VPS if you're doing it that way, that checks the PDF daily, and if the file changes it notifies you - that'd be fairly trivial to setup.