Engineering in the McGraw-Edison era prioritized excess capacity and mechanical over-engineering. The W9’s transformer core was made of high-grade grain-oriented silicon steel, far thicker than modern materials. The enclosures were fabricated from 10-gauge or 12-gauge sheet metal, welded, and coated with baked-on enamel that resisted fading, chipping, and corrosion. Many units still in service today have survived being dropped by cranes, buried in mud, and blasted with winter road salt.

The W9 Portable is a bridge between the steam age and the hydraulic age.

In the realm of heavy construction and earthmoving equipment, the "W9 Portable" is not a machine you will find on a modern showroom floor. Instead, it refers to a specific configuration of a legendary piece of mid-20th-century machinery: the McGraw-Hill W9 Traxcavator.

Produced primarily during the 1940s and 1950s (often under the Terex brand following the acquisition of Euclid by General Motors), the W9 represents a pivotal era in construction history—when heavy equipment transitioned from cable-operated leviathans to hydraulic precision.

Here is a detailed look at the machine, its features, and its legacy.

The W9 is most famous for its role as a Traxcavator—a term popularized to describe a tracked excavator that could also function as a loader.

The "Portable" nature of the W9 gave it a distinct advantage over older "steam shovel" designs:

The price varies wildly based on condition, included cables, and whether the transformer has been tested.

To understand the W9, you must first understand the era. Before the Sony Walkman Professional (WMD6C) or the Nagra III, portable recording was a nightmare of vacuum tubes and heavy lead-acid batteries. Most "portable" recorders of the 1950s weighed over 30 pounds and required a handcart.

McGraw Hill’s industrial division pivoted in the late 1950s to serve the "business communications" market. They saw a need: field journalists interviewing subjects in noisy environments, engineers documenting bridge stress tests, and even the military needing a rugged device for "voice and signature" intelligence gathering.

The result was the W Series. The "W" likely stood for "Wireless" or "Workhorse," but by the time the W9 rolled off the production line in the mid-1960s, it had evolved into a three-motor, direct-drive system that rivaled the professional studio decks of the day—only it fit under an airplane seat.

Key Era: 1965–1975 (Though units were serviced well into the 1980s).