By June of 1917, the expansion of the Field Service and the United States’ entry into the war prompted the Army to federalize the Field Service, forming it into the United States Army Ambulance Corps.

Description: Military tan body, bonnet, closed rear doors, mudguards, running boards and ribbed roof; rear lights in red and type-3 engraved rear doors; military tan 12 spoke wheels on black tyres; radiator grille, windscreen, headlights and side lamps in chrome; black seats and LHD steering wheel in plastic; number '66' on bonnet and rear door and above both side windows with a green shamrock below; a red cross in a white roundel on cab roof, rear door and both side van panels.

Variations: Positioning of 'US' below the shamrock may differ slightly.

Notes: This model is packaged in either a maroon J-type or a straw-style window box.