This 2 foot gauge Beyer Garratt is outside frame, but I think this approach was very rare in a narrow gauge articulated, perhaps due to weight considerations. The outside frame locomotives were essentially standard gauge size. The Rio Grande rebuilt standard gauge consolidations as the K-37 class 2-8-2's and the NdeM converted some of its last 3 foot gauge outside frame locomotives to standard gauge. A standard gauge 2-6-6-2 effectively converted to narrow gauge via outside frame would have been very heavy indeed for the trackage.

The story is that's what doomed the NdeM HR-01 class when the lines to Vera Cruz and Oaxaca were standard gauged. The rail on the remaining narrow gauge to Cuautla and Puebla was too light for the articulateds and the IRCA did not want them. So they were scrapped. A shame as they were probably the most modern 3' gauge steam locomotives. At least in the New World.