Yes, those tall poles are indeed railroad crossing gates. A Santa Fe Railway line crossed Colorado Street at this location.

Apparently, after the rails were abandoned the right of way became an alley. At some point in more recent history it was named Big Bang Theory Way in honor of the TV show of that name set in Pasadena. And adding to the layered history, if you will, the Los Angeles Metro "A Line" (Blue Line) now runs beneath this exact spot.

So many overhead wires and cables again! The modern street views look so uncluttered by comparison, discounting the increased vehicle count on the ground. And what is the 'V' shaped item in front of the line of parked cars on the right? Is it a single construction, or two poles, as on the opposite side of the street?

[Barriers similar to what you'd see at a railroad crossing ? See the comment above. - Dave]

that there's nobody meaner. Is Colorado Street the Colorado Boulevard that was terrorized by the little old lady and her shiny red Super Stock Dodge in the sixties? A Jan & Dean fan needs ta know.

[Colorado Boulevard is indeed the former Colorado Street seen here, and Broadway is now the Arroyo Parkway. - Dave]

I can't seem to find that little old lady or her super stock Dodge.

I sure hope the poor pony didn't have to taste too much of that whip. I'm sure he was pulling with all his might.

Below is the same view taken in April of 2011.

I imagine someone going to the doctor or dentist for the first time in that building, standing outside before entering, locating the window with their doctor’s name, counting to the floor by poking the air with a finger, noting the position in the building, then going in and finding the office accordingly.

[ ... until some killjoy invented the lobby directory. - Dave]

There have been at least two Chamber of Commerce buildings featured recently. Could be a new theme?

I lived in Pasadena from 1994 to 2007, and that building on the right felt familiar. Still there! So many changes, though ... thanks for posting, I always wondered what it was like back in its heyday.

[The Chamber of Commerce Building, completed in 1904. - Dave]

I'm glad to see that he chose dentistry as his practice of medicine. I don't suppose Dr. Reamer would have made a very popular proctologist.