RULE 7. CHANGING LOCOMOTIVES. .(a) A road freight engineer may be required to exchange engines of his own train at points where yard crews or hostlers are employed, as part of his road trip and additional compensation shall not be paid under either road, yard, or hostling rules or regulations.

(b) When a road engineer is required to change the locomotive of his own train at a point between terminals where yard crews or hostlers are not employed, an arbitrary allowance of one hour shall be paid for each such point in addition to all other time on the trip, except such payment shall not apply to an engineer under the following conditions:

1. When the engineer is run for the exclusive purpose of making a change of the locomotive.

2. Where the change in locomotive occurs while the engineer is off duty.

3. Where the change is made due to a failure of their own locomotive.