Denver tramway corporation Radical changes due June 13 for bus lines, 4,5. 1955 Lafayette St residents score partial victory. Office workers union blasts tram agency ban on bus card ads. Post Je 12 '55 p.1$ All-diesel bus service opens with:-2,000 more seats in use. Post -Te 13 '55 P 3 Progress delays reporter. His better bus service 20 minutes later. Post Je 13 '55 p,.j Shakeups in bus service system