Complex sentence: In 1970, NIR started using new rolling stock to re-launch the once-popular "Enterprise" between Dublin and Belfast with three new NIR Class 101 diesel locomotives built by Hunslet in England and Mark 2B carriages built by BREL.
Split into simpler sentences: In 1970, NIR started using new rolling stock to re-launch the once popular "Enterprise" service between Dublin and Belfast. These trains comprised new three diesel locomotives (the NIR Class 101 built by Hunslet in England) and Mark 2B carriages built by BREL.