This must surely be one of the strangest service advisories issued by Amtrak:

http://www.amtrak.com/servlet/Conten...=1189639708788

In short, during the G-20 summit in late September you won't be able to purchase a ticket to/from PGH. You will be allowed to travel through PGH on the Capitol Limited, or connect in PGH (i.e. between the Capitol Limited and the Pennsylvanian), but connecting passengers "will be asked to wait for their connecting train in the station waiting room."

However, connecting passengers are later advised that "Connecting passengers who exit the station must present their ticket stub to re-enter the station." So evidently connecting passengers won't be held prisoner against their will, but going "landside" might be a hassle.

At any rate you could travel "to/from" PGH on the affected days by buying a ticket that connects to the first station beyond PGH, but this would cost more...and I'll bet if you de-trained at PGH with all your belongings you'd get a nice long chat with some adrenaline-fueled cop looking for the big score.

Additionally, an Amtrak spokesperson told a local newspaper that connecting passengers:

Obviously this information conflicts with Amtrak's own Service Alert. Bottom line is you probably want to avoid Amtrak for Pittsburgh travel during that time.