Four-character carve-up of 'Um-bridge':
乌 for 'Um-',
姆 for the '-m-' (Chinese has no syllable-final 'm' in pinyin, so it gets re-syllabified),
里 for '-bri-',
奇 for '-(d)ge'. The
姆 character is the workhorse for English '-m-' or '-mer-' inside foreign names (
汤姆 Tom,
山姆 Sam).