Original sentence: Currently in active service at the Cass Scenic Railroad in Cass, WV.The largest Shay ever built is Western Maryland 6, nicknamed "Big 6"
Edited sentence: Big 6 is Currently in active service at the Cass Scenic Railroad in Cass, WV and is the Largest Shay currently in existence.The Second largest Shay ever built was Western Maryland 6, nicknamed "Big 6"