Logbook: Machine Learning approaches
How are you solving this? How are you keeping track of the work done?
  What's your logbook tool?


This might not be the best approach. But, this is how my team does it. We believe that for pulling off an end-to-end data science experiment, proper conscience is very important. So, we use Slack for the same for our discussions and the meetings.

In addition to them, we have Rmd (R markdown) files for documenting the planning and the analysis parts.