49 CFR §212.211

1. (a)The apprentice S&TC inspector must be enrolled in a program of training prescribed by the Associate Administrator leading to qualification as a S&TC inspector. The apprentice inspector may not participate in the investigative and surveillance activities, except as an assistant to a qualified State or FRA inspector while accompanying that qualified inspector.
2. (b)Prior to being enrolled in the program the apprentice inspector shall demonstrate:
   1. (1)Working knowledge of basic electricity and the ability to use electrical test equipment in direct current and alternating current circuits; and
   2. (2)A basic knowledge of S&TC inspection and maintenance methods and procedures.