Unladen African or European crow?
Hey, by the way, a note about the new MRT extension. I've been watching the progess of the new extension by noticing changes between Taipei Main Station and Banqiao Station. Signs have started changing, some maps are updated, etc. However, there is one potentially troubling thing, considering your desire to go to Yongning Station.
You know how the MRT trains display the terminal destination station on the LED signs on the outside of the train? Well, as late as Thursday (yesterday), all of the trains headed in the direction of Yongning displayed "Far Eastern Hospital". The significance of that is that if F.E.H. is really the terminal station for the moment, due to some construction issue, etc., then the train isn't regularly going to Yongning yet.
I don't know the answer. Something that you might want to check out before tomorrow morning. The MRT has a 24-hour toll-free number, but I don't know what it is.
Back to laying down and wishing people here understood the purpose of pain medication...
P.S. - A map of the Yongning station area. Enjoy.
EDIT - Friday, 9:50pm - My wife got stuck on the blue line extension yesterday (forgot to get off) and so went to the end of it out of curiosity. She says it goes all the way to Yongning regardless on the LED signs on the trains. Hope that helps.