Complex sentence: To circumvent constant bottlenecks near Philadelphia, the PRR constructed a low-grade double-track electrified freight line in 1906 to bypass the steep grades and busy Philadelphia suburbs.
Split into simpler sentences: To circumvent constant bottlenecks near Philadelphia, the PRR constructed a low-grade double-track electrified line in 1906 to host its freight traffic. This was done to bypass the steep grades and busy Philadelphia suburbs.