The layout of the Vienna railway network was also influenced by its uses for the military which demanded full compliance with mainline railroad rules, steam propulsion and integration with ordinary rail service; this increased costs compared to electrical light rail option. When the lines opened, in four stages between 1898 and 1901, they failed to attract mass riders due to high costs; affluent passengers were discouraged by dirt from engine smokestacks and slow speed. While primarily an urban railway line, some trains continued on the mainlines to the north and west of the city.