I use the CIF native format. For the past so many years I've downloaded the weekly update from the RDG website at
https://data.atoc.org/data-download. However, from the start of the new year the Timetable Feed stopped being updated? I sent a ticket via the Contact Us page but never received a reply. This happened before and for a few weeks I was able to download from a mirror, provided by Peter I believe. This time around I couldn't find same mirror but with the help from other more recent posts I was able to download from
https://datafeeds.networkrail.co.uk/ntrod/CifFileAuthenticate?type=CIF_ALL_FULL_DAILY&day=toc-full.CIF.gz. This Saturday however that download was just a tenth the normal size? Was this an update and not the full CIF? Back over on
atoc.org I saw the TF was now up-to-date so I just used this instead and didn't investigate further. I see all the posts about missing CIF file but taking a path of least resistance approach and as the above still just about works for me I thought not to muddy the waters further. But since you ask!