Sentence:  Are we to blame Livingstone for Tube overcrowding? In part, yes, but as Sir John Eliot had observed in 1955, while Chairman of the London Transport Executive: 'They're not <WSD>crammed</WSD> in. They <WSD>cram</WSD> themselves in.' 
Meaning of the word marked with <WSD> tags:  To press, force, or drive, particularly in filling, or in thrusting one thing into another; to stuff; to fill to superfluity.