Input (grade 11): The OIR operated its own fleet of steam locomotives: 0-6-0T and 0-6-0ST locomotives built by Hunslet and 0-4-0ST's built by Hudswell Clarke.
Output (grade 7): The OIR operated its own fleet of steam locomotives: 0-6-0T, 0-6-0ST and 0-4-0ST's.