One question that's come in this group a couple of times is how do you
get historical data for bike and dock availability.
While you can get current data from the station information web service,
in order to get historic data you'd have to anticipate your need for it
ahead of time so that you get it from the retail feed and store it.
A member of this group asked about it back in February and I suggested a
hack to estimate this. I've turned the hack into an article for TDS:
https://towardsdatascience.com/estimating-bike-availability-from-nyc-bike-share-data-7cfc4655d5f6