Expired bus schedules up to 2 August 2018 are now available at:
http://bus.data.tfl.gov.uk/expired-schedules/ExpiredSchedules.zip
This data is 37.8 GB in size when unzipped.
Yes. About 57,000 expired bus schedules! The files are in XML form but open in Excel (though one user has reported difficulties in doing this in, I think, Excel 2016).
Simply opening the files in Excel and resaving them as .xls or .xlsm drastically reduces the size of the individual files. However doing this and the zipping all the Excel files would probably not have reduced the size of the zip file - XML tags make for very large files but also very efficient compression.
Of the 57,000 expired schedules, about 17,000 have previously been made available in PDF form (access easiest via googling Working Timetable Graveyard). The set of information in the XML files is slightly different to that in the PDFs and neither is a subset of the other as far as I can see.
The next “trick” is to make the individual files available. That is going to requires some thought, not to mention time.
For those interested in accessing the individual working timetables, you can get Excel files (which have been derived from the original XML files) via London Bus Timetable Graveyard.
The same source also gives access to the more recent WTTs made available over the last few years by TfL in PDF form.
Overall, a mere 77,000 schedules or so!
Michael