The real challenge to the project for Digging & Rigging, Inc. was not in its assembly or even in the self-erection of its 435-foot-long boom and jib combination. The "white knuckle" concern for the owner of the massive new 300-ton capacity Link-Belt crane was in walking the massive machine about 300 feet, as the crow flies, from the assembly area to the tower site with the boom in place.

There was an incline of slightly over 13 percent, or 7 degrees uphill, on a freshly excavated dirt roadbed that had to be negotiated during the move. The entire trip across the asphalt parking lot on timber mats and up the wet dirt slope went smoothly.

The weather was the only factor to adversely affect the progress of the job. It rained over 3 inches the first nine days of April causing difficulty and delay in assembling the crane and the segments of the tower. For understandable safety reasons, the Wolf erection tower technicians do not work in the rain.

There was also a slight concern about the transition of the heavy 348Hylab5 crane from the timber mats to the recently cut earth road, but that, too, went without incident. The Link-Belt crane's powerful 6-cylinder, 476-horsepower diesel engine had power to spare. Jim Gregory Jr., Digging & Rigging's vice president, lowered the boom slightly (10 degrees to 15 degrees) as he made the climb so as to better enhance the machine's overall balance. "We inched up the slope without hesitation, idling at 800 rpm."

The crew assembling and erecting the crawler crane, with its combined long-reach boom and jib, actually encountered only one problem. They had to remove some of the paint in the boltholes. Other than that it was a professional textbook operation.

Sixteen flatbed truckloads hauled the crane's components from Digging & Rigging, Inc.'s Hagerstown, Maryland, yard, over the interstate highway system, to a closed MDOT truck scales parking area just off the southbound lanes of I-270 near Hyattstown, Md. Even then, only the base crane's 12-foot-wide load required an over-the-road police escort. The tracks, counterweights, boom, and jib sections arrived on-site unescorted.

The dictionary defines the word "slick" as deftly executed and/or adroit. And that best describes the Digging & Rigging operation in reassembling the crane to erect the new self-supporting television broadcast tower.

The overall project, according to Carl Wolfe, chief engineer of Transmission & Distribution for Maryland Public Television (MPT), was being done for them. The 450-foot tower, manufactured by Sabre Communication of Sioux City, Iowa, is one of six that MPT has strategically positioned throughout the state. Unlike the existing towers, the new towers are capable of supporting the new antennas required for digital television transmission. Each site also required a transmitter. Once the tower was erected, a steel platform was placed on it followed by a 28-foot-tall antenna, weighing approximately 3,500 pounds.

Interestingly, the new tower is one of only two short towers in the MPT system. The other four are all guyed towers in the 800-foot to 900-foot-tall range. The two shorter ones are each located on high hillside sites.

Sabre Communications engineered, fabricated and shipped the tower unassembled to Maryland. They retained Wolf Contractors of Marriottsville, Md., to handle the site preparation, foundation construction and tower erection. In the case of freestanding towers, general manager Dave Wolf said that they are normally self-erecting using an ascending gin pole to raise them as they go.

In this instance, however, time was of the essence. Using their Link-Belt 348 crawler crane do the work, Digging & Rigging completed the project in days instead of weeks because the tower placement was already a year behind schedule. The crane method was also safer. The tower was prefabricated on the ground in sections and these were then assembled in the air.

Wolf excavated the base support pad foundations and placed the heavy reinforcing steel in them. They then contracted TBK Concrete Construction Co. Inc. of Edgewater, Md., to supply and pour 396 cubic yards of concrete for the foundation.

Wolf crews assembled and erected the first 100 feet of the tower from the ground with the assistance of Digging & Rigging cranes, including a Link-Belt HTC 8660 and a 150-ton machine to erect the next three tower segments. The triangular tower's base section has three 39-foot-wide faces. Each leg was fabricated of solid steel as per state specifications rather than from the more conventional hollow steel pipe. These were set individually and connected together on the ground.

Digging & Rigging, Inc. then moved in their new Hylab 5 crawler crane with its long reach lattice boom and jib. The first lift made with it weighed 12,770 pounds. This 20-foot-tall section of the triangular tower had three faces, each 25 feet wide. The crane was working at a 92-foot radius. The boom angle was 82 degrees.

The final section of the tower weighed 14,700 pounds and was 90 feet tall with 9-foot-wide faces at the bottom, tapering to 7 feet wide at the top. This was the heaviest and highest lift on the tower. To facilitate its balance and vertical placement, the crew positioned the lifting slings on this section 25 feet below its top, giving operator Dennis Caniford all the challenge he could handle considering the crosswind blowing at the 360-foot tower elevation and the safety of the three Wolf tower technicians waiting to make the final connection.

The final move at the television tower was to walk the massive crane down from the tower site to the truck scale parking area where it was disassembled. The reverse procedure was used and it also went without incident. Observers at the location timed the downhill speed at "four crawler pads or 52 inches in 30 seconds."

Digging & Rigging, Inc. was founded in 1981 by James E. Gregory Jr. Originally it was a local excavation company with one Case loader/backhoe and a single-axle dump truck. Then came their first crane. Now they are essentially a crane rental service, doing very little dirt work. Susan Gregory, Jim Jr.'s mother, is the firm's president; he is vice president; and his father, Jim Gregory Sr., is general manager.

"We are considered to be a comparatively small specialized company. We work primarily in the mid-Atlantic states, principally in Maryland, Virginia and the District of Columbia area," said James Gregory Jr. "However if the job is right for us and we have the cranes for it, we are available to undertake it anywhere. We have a select client list of repeat customers who we have served over the years. They come back to us often because our philosophy is to do whatever we do right — the first time."