I started my one-day trip to San Bernardino from Baldwin Park train station. I went there by Metrolink train. I purchased a return ticket for USD 17.5. It was not too bad as the train was prompt, clean and convenient.
Inside the train...
There are nine stops during the trip: Covina, Pomona (North), Claremont, Montclair, Upland, Rancho Cucamonga, Fontana, and Rialto.
Views from the train:
And finally... St. Bernardino Train Station