A prototype fitted with King Telstar aerial cabling equipment to allow cabling to continue whilst the vehicle was moving.
Pictures are taken at Bletchley Park Training School
The top two pictures show short poles which were used for overhead line training
TELSTA SPEEDS AERIAL CABLING
Anew machine which, operated by only two men, can erect aerial cables four times as fast as the normal four-to-five-man gang, is undergoing extensive field trials in the Shrewsbury Telephone Area.
It is the American-manufactured Telsta T36 - more prosaically called the Aerial Cabling Unit in Britain - and is being used in rural areas to put up the aerial cables which are rapidly replacing the familiar telephone wires. It can erect aerial cables at the rate of between four to six miles a week, the machine paying out the cable in mid-air from the end of its electrically-operated boom as it is driven along at walking pace.
The Aerial Cabling Unit consists of a turret-like base and a main boom fitted with an extending inner section. The working platform, in the form of a metal basket, is supported on steel arms at the end of the telescopic boom which has a horizontal reach of 25 ft. 11 ins, and a vertical reach of 36 ft. The complete assembly is mounted on a Dodge vehicle chassis with a two-speed rear axle and a new type of differential lock consisting of two rollers which can be made to bear against the rear wheels to prevent wheel spin in mud or snow.
The boom is easily and rapidly raised, lowered or rotated by means of a hand-operated joystick, power being obtained from a propane-driven electric generating set, with an electric self-starter, mounted at the rear of the chassis. The generator drives a number of electric motors which move the boom through a series of chains and chain wheels. If a chain breaks, the working platform can be manually rotated and safely lowered to the ground.
The new unit can carry more than 30 cwt. of cable on two arms at the rear of the chassis so that additional cable-carrying transport is unnecessary. The arms can be hydraulically raised and lowered for loading and unloading cable drums. The payload of the basket is five cwt. and in addition nearly a ton of suspension wire can be carried in the well of the vehicle.
As the machine moves along its route between poles, the aerial cable can be paid out under tension obtained by electrically-operated drum brakes mounted on the cable drum spindles and controlled by the driver in his cab. The machine stops only briefly at each pole, the operator boring a hole through it with a quick-change combined electrical drill and torque wrench, passing through a bolt and tightening the clamp with the wrench. This operation takes only a few minutes.
The machine also has a small but powerful three-speed winch so that at no stage does cable have to be manhandled. This winch - called the electric towline - is used by the Americans to carry out a number of specialised tasks, including passing cable behind poles.
Shortly after the machine arrived in Britain from the United States, Mr. J. S. Kennedy, factory manager of the Telsta Corporation, was flown over to supervise the training of Post Office teams in its use and maintenance.
First reports indicate that the trials will be successful and that use of the new Aerial Cabling Unit will not only increase productivity but also take much of the hard work out of aerial cabling.
Last revised: February 06, 2021