Märklin / Marklin BR78 5707 Gauge 1 / Spur 1 Chassis Block

This is a 3D recreation of the chassis block (frame block) used in the Märklin BR78 5707 locomotive in Gauge 1 (Spur 1). The original locomotive and replacement parts are no longer in production, making accurate reference material difficult to obtain.

The model was recreated using caliper and micrometer measurements from the original component, and is dimensionally accurate to approximately ±0.5 mm.

The original parts were manufactured as follows:

Chassis block / frame block: die-cast metal

Keeper plate: die-cast metal

Brake gear: injection-molded plastic

Because the original parts were cast metal, successful 3D printing is not guaranteed. Print parameters will depend heavily on your printer, material, and intended use. This model is primarily intended for reference, planning, and photogrammetry purposes, though it may also be usable for other experimental applications.

Historical Note

The BR78 5707 chassis block is historically notable because it was used as the mechanical base for building Oliver the Great Western Engine during the original Thomas & Friends model series production.

For this reason:

The coupling rod in this project is modeled in its trimmed form used on the Oliver prop.

The center driving wheel (which had a larger counterweight and longer crank pin on the Oliver model) has not yet been modeled or included in this release.

Possible Uses

This model may be useful for:

Gauge 1 / Spur 1 model train research

Oliver the Great Western Engine prop or replica projects

Reference for Märklin BR78 5707 chassis construction

Historical documentation of Märklin Gauge 1 components