603 (1917) (obligation to furnish passenger company on a department line formerly devoted solely to carrying freight) Lake Erie & W.R.R. 262 (1910) (obligation to run a normal passenger practice as a substitute of a mixed passenger and freight teach) Chesapeake & Ohio Ry. 209 Chesapeake & Ohio Ry. 208 Chesapeake & Ohio Ry. Public Comm’n, 267 U.S. So. Ry. v. Clough, 242 U.S. Public Serv. Comm’n, 242 U.S.