Well, as I have ZVV pass in Zurich, I thought of swiping SBB app in Enge on my way to Zug. The plan backfired. The mobile swipe feature was unresponsive and I got out of train to get the GPS signal, and the train doors shut off. I had to be in Zug in 30 mins for an appointment I can't miss, so I took a 100 CHF Uber from Enge to Zug. Worse, I forgot my detachable sunglasses in the train, but luckily my friend in Zug went to the station in time to get them for me. Phew!
I arrived in Zug right on time, finished all of the pending tasks, met a couple of ex-work colleagues/friends for lunch. Now back in Zurich, and getting ready to go to my final Summer Tennis training session. Looking forward to it!