Never write new code on a train. I've learned this lesson many times. The WiFi is not reliable, the offline documentation is spotty (with the exception of emac

Never write new code on a train. I've learned this lesson many times. The WiFi is not reliable, the offline documentation is spotty (with the exception of emacs), and you'll waste more time than needed trying to do things the wrong way instead of searching online for solutions later. No new code on the train. Optimise existing or fill in some TODOs. No new code on the train.