Complex sentence: In 1977, pantograph gates, salvaged from retired R1 through R9 cars, were modified and installed on the front ends of the R42s and baloney coiled spring type inter car safety barriers were installed on the blind ends of the married pairs.
Split into simpler sentences: In 1977, pantograph gates, salvaged from retired R1 through R9 cars, were modified and installed on the front ends of the R42s. Baloney coiled spring type inter car safety barriers were also installed on the blind ends of the married pairs.