Like some of the others, I found the CS wifi to be not working at all during my trip in March - meanwhile my mifi (off the verizon cell network) was working fine in the PPC.
Everyone who has complained so far on the grounds that Amtrak's wi-fi was not working but my cell/Mi-fi was working, please realize that Amtrak's wi-fi is bandwidth-limited as in, a hundred people are trying to access the internet using one access point while on your cell/mifi its just you connecting to the tower, so the probability of getting a connection through is much greater on your personal device than a shared wifi. To make a fair apple to apple comparison between Amtrak's supposedly-crappy wifi and internet connectivity using personal devices, only one passenger should be using the train's wifi at a time. Maybe the Dining Car attendant can issue "reservation slots" to individuals for wifi usage