Some notes about Caltrain after riding it a few times recently:
Caltrain is a single train line that runs from SF to San Jose. It has stops at all the important Bay Area cities that lie on this path.
Information about schedules, stations and fares are at their website.
There two different schedules: for weekdays and for weekend.
There are 3 types of trains described on the schedule.
Local: One of these runs every hour. This will stop at all the stations along the route. This one takes 1h 30m to complete the full route from SF to San Jose (or the other way around).
Limited-stop: There are a few of these during rush hours. This one skips some of the stations. This one shaves 15 mins from the Local and finishes the full route in 1h 15m.
Baby Bullet: There are a few of these during rush hours. This one skips more stations than Limited-Stop. This one shaves 15 mins from the Limited-Stop and finishes the full route in 1h.
All Caltrain carriages are double-storey, like double-decker buses. Seating is comfortable. I saw that most office folks make work calls or work on their laptops on the ride.
You can take your bicycle on the Caltrain. There are 2 cars with bike racks inside where you can fasten your bike.
The entire line is broken into 4 stages. Your ticket price will depend on how may stages your route from source to destination spans.
To ride the Caltrain you can buy tickets, passes or use your Clipper card.
If you use the Clipper card, remember to tap both before you board at the source and after you get down at your destination. There are Clipper card tap stations along the platform at all stations except SF, where they are inside the station.
Accessibility: SF station is 20 mins walk from the financial district. You might be able to find MUNI or railcar stops closer. For the rest of the stations, accessibility can be a hit or miss. There might be VTA buses or train stations near the Caltrain station. Else you will need to take Uber or have family/friend drop you off or pick you up.
There are no toilets at any of the stations, except SF. The SF toilet is super-dirty and super-smelly, and seems to be used mostly by homeless folks.
If it is raining or sunny, there is no shelter or overhead cover on the platforms at almost all stations, except SF.
The displays on the platforms at the stations show time and status of two upcoming trains.
A ticket checker will do a round checking tickets on each ride. If you did not buy the right ticket, you will get a notice of violation and fined $90 or so. I saw this happen to a tourist who had mistakenly bought a single-stage ticket and was traveling across multiple stages.
The ride is comfy. For occasional visits to SF for single folks, couples or friends, Caltrain seems better than being stuck on slow-moving 101 in a car, dealing with traffic entering SF and then finding and paying for parking. For families with kids, Caltrain is difficult because I didn't see much parking for cars near Caltrain stations and also young kids need a child seat if you take Uber.