>The museum owns 4 acres of land adjoining the SN line at Molena so building a loop would not be out of the question. However purists would complain that since SN never had a loop there, the museum should not build one no matter how practical it would be for running single-end cars or short rains pulled by one locomotive

Do these same purists object to electrifying the line at 600 v DC when the SN never used 600v? Do they object to running cars from the P&SR and Peninsular Rys, the Crandic, and Key Units on the line? The SN never did that either. A loop is eminently practical for all trolleys, big and small, and not just the single-ended ones. It's far, far safer than backing up and and less time consuming than running around a train.