Alfa Romeo RM Four-Wheel Drive Winter Sports Half-Track chassis 12023

Alfa Romeo RL & RM chassis 12023 is a 1924 (possibly late 1923) RM Prototype / Four-Wheel Drive Half-Track bodied by Unknown (factory-based conversion).

An extraordinary Alfa Romeo RM chassis 12023 fitted with a Kégresse-Hinstin licensed half-track system, believed to be the sole surviving Alfa Romeo four-wheel-drive winter sports vehicle.

Factory specification

Manufacturer: Alfa Romeo
Model: Alfa Romeo RL & RM
Variant / Type: RM Prototype / Four-Wheel Drive Half-Track
Year: 1924 (possibly late 1923)

Chassis number: 12023
Engine number: 12023
Gearbox number: Alfa Romeo 4-speed manual with auxiliary dual-range transmission
Body number: Open touring body with rear seating
Coachbuilder: Unknown (factory-based conversion)

Engine size (as built): 1,944 cc
Engine size (current): 1,944 cc (modified to dry sump specification)

Body style / type (as built): Open four-seat winter sports tourer
Body style / type (current): Open four-seat half-track configuration

Colour (as built): Unknown
Colour (current): Patinated original finish

Interior colour (as built): Period specification
Interior colour (current): Original patinated trim

First completed: Early 1924 (possibly late 1923 prototype range)
First delivered: Exported new to United States
First dealer / destination: New England, USA
Original registration: Unknown

Notes: RM chassis 12023; early production-range number; fitted from new with Kégresse-Hinstin licensed half-track system; believed unique surviving Alfa Romeo four-wheel-drive half-track.

Registry: Alfa Romeo RL & RM/Chassis Registry

Ownership history

No.	Owner	Location	Occupation / Notes	From	To
1	First owner (name unconfirmed)	New England, USA	Reportedly exported new for winter mountain use	c.1924	Unknown
2	Long-term private ownership	New England, USA	Retained in largely original condition for decades	Mid-20th century	Late 20th century
3	Subsequent private owner	USA / UK	Imported for specialist inspection and preservation	Late 20th century	—

Registration history

No confirmed period registration records documented.

Competition history (period)

No competition history recorded. Vehicle believed constructed for winter transport and sporting use rather than racing.

Appearances and non-competitive events

Year	Event	Driver(s) / Exhibitor	Notes
2005	Retromobile (reference comparison)	—	Early Kégresse licence numbers compared with Sahara Citroën exhibits

Technical specification and drivetrain configuration

Chassis 12023 is based upon the Alfa Romeo RM production chassis, using the standard 1,944 cc four-cylinder overhead-valve engine. The engine was modified to dry sump lubrication, presumably to accommodate steep gradients and lateral inclines encountered in mountainous terrain.

The drivetrain incorporates:

Alfa Romeo 4-speed gearbox
Original RM transmission brake
Secondary transmission housing incorporating dual-range gearing
Propeller shaft driving rear track mechanism

The track assembly is based upon the Kégresse-Hinstin system, manufactured under licence from André Citroën. A plaque mounted on the bogie reads:

“Propulseur – Kegresse-Hinstin (Licence 48) André Citroën”

Front wheel hubs display the Citroën gear motif.

The Kégresse concept, developed by Adolphe Kégresse for Tsar Nicholas II, utilised flexible track systems to enable reliable travel over snow and soft terrain.

Chassis and production context

RM chassis numbers are recorded as running from 12001 to 12265 (1923–1924 production). Early numbers are believed to have been allocated to prototype or special-purpose builds.

At chassis number 12023, this vehicle likely dates to very early 1924 or possibly late 1923 production.

The exceptionally low Kégresse licence number (48) further suggests early adaptation of the system.

Condition and preservation

The vehicle survives in largely original condition:

Original patinated rear seating and grab handles
Period wooden skis designed to be mounted beneath the front wheels for difficult snow terrain
Complete track and transmission assemblies

Following inspection by Alfa Romeo specialist Jim Stokes (UK), the engine was reported to start readily by hand crank with good oil pressure, and the drivetrain was described as operational.

Historical significance

Chassis 12023 represents an extraordinary and highly unconventional application of the Alfa Romeo RM platform.

Believed to be the sole surviving Alfa Romeo four-wheel-drive half-track, it reflects an experimental or special-order adaptation intended for winter mountain use, most likely in North America.

Its survival in largely unmodified condition provides rare insight into early interwar experimentation with alternative driveline and mobility solutions. The integration of Alfa Romeo engineering with licensed Kégresse track technology makes it a unique hybrid of Italian and French mechanical innovation.

Notes

Described in auction literature as the only surviving Alfa Romeo half-track.
Early RM chassis number suggests possible prototype or special build status.
Dry sump conversion likely period modification.
Export documentation and factory build records require further archival confirmation.
Total RM production approximately 1923–1925 within chassis range 12001–12265.

Sources

Auction catalogue description (1924 Alfa Romeo RM Four Wheel Drive Winter Sports Half Track)
Inspection notes (Jim Stokes, UK)
RM chassis production data (1923–1924)
Kégresse-Hinstin historical records