Complex sentence: With such a traffic density, the expense of electrification could be recouped easily by savings, and in 1928 this happened, the existing cars being fitted with electric motors, trolley poles and control stands and the steam locomotives disposed of.
Split into simpler sentences: With such a traffic density, the expense of electrification could be easily recouped. By 1928, all existing cars were fitted with electric motors, trolley poles and control stands and the steam locomotives disposed of.