Rivnuts from Homestead, PA on 2/14/2022 4:44:16 PM:
I have taken the Amtrak Capital Limited from Pittsburgh to DC via Cumberland. The train leaves Pittsburgh at 5:20 AM if it is on schedule and arrives in Cumberland 4 hours later at 9:20. This arrival time would allow you to start your bike trip back to Pittsburgh and get a full day of riding depending on your travel date and the time of sunset at that time. If your dates are firm and you are bringing your bikes to take on the train, you need to get your train reservations early so you can get the requisite add-on reservations for your bikes. Bike capacity on the train is limited so bike reservations can be hard to get on short notice.
The train station in Pittsburgh is in close proximity to several downtown hotels. If you are staying at one of those hotels the night before your departure, the hotel often will allow you to park there for free until you return to Pittsburgh. Aside from that there is little free parking near the train station. There is a parking garage direct across from the train station but you may find it a little expensive for your taste.