The Adoption of a Standard Gauge System for All Railroads________

The adoption of a standard gauge system for all railroads________ .

A) allowed all rails to be built of steel instead of inferior quality metal
B) allowed trains to travel on all tracks, thus integrating the entire system
C) kept all trains running on the same time schedule
D) allowed tracks to be built on both government and private lands
E) kept the trains from derailing so often and so disastrously