score:14
Single ride tickets "are valid on board any Capitol Corridor train/bus at any time between the stops noted on the ticket." And from their ticketing policies:
Itinerary Changes
Since Capitol Corridor does not require advance reservations, most Capitol Corridor tickets may be used on the Capitol Corridor route within one year of purchase without modifying your ticket. You will, however, need to modify your ticket in the following circumstances:
travel requiring a reservation, such as those on certain connecting bus routes, or trips that include travel segments beyond the Capitol Corridor route,
tickets that were booked as part of a limited-time, reservation-required promotion, and
group tickets or tickets issued by a travel agency)
You can also purchase tickets with the Amtrak app, so you wouldn't need to buy until shortly before you board the train.
However, if you book at least 24 hours in advance, you can get a group discount after the first full fare.
Upvote:7
You do not reserve a seat on any specific train on the Capitol Corridor. From their FAQ:
Do I need to make a reservation?
No. Capitol Corridor is an unreserved route, so no reservations are required, and you can buy your tickets at any time and easily hop on board! Some connecting bus routes require reservations, however, so please make sure to purchase those tickets in advance. Certain promotions and discounts may require advance purchase as well.
ADDENDUM
Note that in the U.S., a reserved train ticket means that you purchase a ticket for a specific train on a specific service at a specific date and time. An unreserved ticket means you purchase a ticket for a specific service but can use it for any train operating that service at any date and time (until the expiration of the ticket). It has no relation to assigned seating, as it is not possible to reserve specific seats anywhere in the Amtrak system (sleeper berths are another story). All seating on all trains is first-come, first-served, but on a reserved train you should almost always have a seat somewhere, even if you are the last to board.