A railway turntable is a an apararus used to turn a locomotive around so that it can move back in the direction from which they came in a very short distance. Railway turntables are often used in places where space is to limited to build a wye. Turntables are usually built as part of roundhouses. It is understood that there were very few turntables in Puerto Rico and the only one that survives today is the one inside the remnants of the Aguirre sugar mill in Salinas. It's builder plate in exhibition in the museum (fig.1) helps us tell the story of this unique part of Puerto Rico's railroad history.

The turntable at the Aguirre sugar mill is an integral part of the structures that make up the Ponce & Guayama Railroad roundhouse. The structures, part of the railyard, is located on the northeastern side of the mill (fig. 4). The roundhouse is a semicircular structure made of steel girders covered with corrugated steel panels (fig. 5). The original roundhouse structure was built ca.1903 and rebuilt ca.1950. The roundhouse served as a service area for the mill's locomotives. The building had six service stalls in the early years. Two additional stalls were added to the north side. The expansion may have happened during the building reconstruction in the 1950's. The compound also includes a small building for diesel engine repair. Rails extend from the turntable all the way into the building's interior.

The turntable is installed in a round pit located on the northwest side of the roundhouse (fig.4). The purpose of the turntable was to allow the movement of locomotives from the spur to the the multiple service areas of the roundhouse (fig.6). The turntable at the Aguirre sugar mill was manufactured by the Philadelphia Turntable Company in Pennsilvania, U.S.A. in the first decade of the 20th century. The company specialized in turntables for many different applications including railroads. The company's adds (fig.7) were appear often in railroad industry publications of the first two decades of the 20th century. The turntable is of the balance type on which a locomotive must sit right on top of the center pivot. This allows it to be rotated with little effort. This design patented by F. H. Saylor in 1887 (fig.8) allows the structure to tip freely without damaging the center pivot when a locomotive enters the turntable. The structure consists of two beams composed of seven iron plates riveted together and mounted on a center pivot base that allows free rotation. This design had wheels on each end that ran over a rail mounted along the periphery of the pit. There balanced design allowed the turntable to be rotated with little effort. The Aguirre turtable was moved by mill workers manually (fig.9,10,11).

Figura 11. La mesa giratoria en ación. | The turntable in action.

Película 8mm por Dave Deyo

At present (2021), the Aguirre turntable and round house as well as the rest of the facilities of the old Aguirre sugar mill are in an advanced stage of deterioration, something that is evident in satellite imagery as recent as 2017 (fig. 12). At present, the man beams of the round table are very corroded, victims of the the water that accumulates in the pit durng times of heavy rainfall (fig. 13). The wood of it upper surfaces is either roted or plain missing.