The 2 and 4 buses both run down Sunset. If you’re near Santa Monica, Sunset or Hollywood Blvds, you can get on any of these buses and end up at Machine, just get off at Alvarado. The 704 is a good express “Rapid” bus you can take from can take from Union Station getting off the red line, gold line, or LAX Flyaway bus.
Red Line Subway
If you’re near the Red Line (or your can connect to it from the Gold or Blue lines), the closest stops to Machine are: Westlake/MacArthur Park, Santa Monica/Vermont, and Sunset/Vermont.
From MacArthur Park, take the 200 bus north about a mile and a half to Sunset (but watch out because this bus might not run very late at night). The park is far less “edgy” than it used to be (more expensive art lofts, no floating bodies), but walking this route in the dark should still be undertaken in the jaunty spirit of adventure.
From Santa Monica/Vermont or Sunset/Vermont, pretty much any bus going east should go to Sunset and Alvarado. (The walk is longish. The bike ride, an exhilarating car dodge.)
Note: Bikes are allowed on the trains, outside of rush hours.
Express Buses from the West
Take the 720 Wilshire Rapid Bus to Alvarado, in MacArthur Park
There’s also a Santa Monica Big Blue Bus which has a “freeway express” (the #10) to downtown LA, at which point, biking, MTA bus or subway+bus become reasonable options.
Note: Santa Monica and MTA are totally unrelated transit systems — waving the pass of the wrong one at your driver will get you frowned at.
From points east and south of Echo Park: The 704 “Rapid” is a great bus you can take from Union Station as you get off the red line, gold line, or LAX Flyaway bus.
If you’re not in LA proper, there’s Metrolink trains to Union Station. From there take the 704 express going West to Santa Monica
By bike from Union Station, take Caeser Chavez west, which quickly becomes Sunset. Keep going 3 miles. Turn right at Alvarado
Honestly, if you’re not too far away, the best way to get there for evening events is bike. Riding Sunset is easy; there’s a bike lane (watch out for doors). Just make sure to bring a real u-lock, not some cabled gadget, because bike theft is rampant in Echo Park.