True, but because Bratkinson said "At least if the Cap is running quite late, you can purchase another ticket PGH-WAS on your cellphone", I was speaking in the context of being able to take the Capitol all the way to D.C. There is never a case where you need to personally purchase a ticket on a different train if you're going to miss your connection on Amtrak.
I generally try to 'think ahead' and solve the problem myself before 'the company' (Amtrak (and airlines, in days gone by)) comes up with a solution, like busing.
Living in the Springfield MA area, a couple years ago I was booked on NEC train #141 to WAS, then #29 to CHI. Historically, it is almost always less costly to go that way vs the Lakeshore Ltd or Cardinal, and only sometimes did the computer 'offer' connecting via the Pennsylvanian at PGH. As a railfan, I'll usually try to maximize my train time for the least cost. So, 2.5 years ago, after a CSX derailment in suburban WAS on the route of the Capitol Ltd, 2 days later, when I was booked to take #141 to WAS and #29 to CHI, I knew the line was still blocked and #30 turned at PGH to go out as #29 at midnight. So, while aboard #141 somewhere south of New Haven, I contacted Amtrak ticketing, told them the situation, and that I would get off at NYP and take the Pennsylvanian to PGH to 'meet' my roomette. Unfortunately, the Amtrak computer couldn't/didn't release 'my' roomette for rebooking. So I got booked into another roomette. I think I came out ahead, as the 2 or 3 busloads of passengers from WAS and points in between were non-stop grumble, grumble, grumble about their rubber-tired journey.
A year and a half ago, on my AGR Points 'vacation', I was booked on the Coast Starlight LAX->PDX, but UP had a derailment on a bridge north of Sacramento which cancelled the Coast Starlight indefinitely (for the first week or so). So, I figured out how to salvage my vacation checking for roomettes on a variety of trains before calling Amtrak and changing my reservation to bypass the CS. I ended up doing a couple of 'shorts' (3 different roomettes for one night only on the 3 night #422 LAX-CHI) and booked #30 to WAS then #148 home to SPG. Had I simply gotten to LAX and then headed to the ticket window when told of the Coast Starlight cancellation, I would have been left holding the bag as at that point in time, 'no alternative travel available', ie, no buses, planes, or anything else. Just a refund of the CS portion of the ticket (AGR points) and I'd be on my own to get to PDX.
I should note that since the June 6 NEC time table revision to coincide with the launch of the CTRail 'Hartford Line', train #148 (last train to SPG) leaves WAS 2 hours later, giving an almost 4 hour layover from #30 in WAS. I've done that twice already. It sure beats my formerly 'sweating bullets' to make the connection if we left Cumberland 2 hrs late, give or take. Nowadays, it looks like that connection is 'made' almost all of the time.