What code regulates power boilers used in locomotive service?

The correct choice pertains to ASME Section I, which specifically addresses the requirements for Power Boilers. This section of the ASME Boiler and Pressure Vessel Code provides comprehensive regulations regarding the design, fabrication, installation, inspection, and testing of power boilers used in various applications, including locomotive service.

Power boilers are integral to locomotive operation, as they generate the steam necessary for propulsion and other functions. ASME Section I ensures that these boilers operate safely and efficiently, maintaining strict compliance with engineering and safety standards tailored to the unique conditions found in locomotive applications.

In contrast, the other codes mentioned focus on different aspects of boiler and pressure vessel standards. For instance, ASME B31.3 pertains to process piping, which does not cover the specific requirements for power boilers themselves. ASME Section VII primarily deals with the rules for the construction of reheaters and heat exchangers in a different context, while CSA B52 addresses refrigeration safety and does not apply to power boilers at all. Therefore, ASME Section I is the appropriate regulation for power boilers in locomotive service.