Over time the constant movement of traffic over the track causes gaps to form in the ballast structure known as 'voids'. Often, from the trackside, sleepers can be clearly see bouncing up and down as the wheels pass over them. Excessive movement is dangerous, of course, so the voids need to be filled to give a firm base for each sleeper. This has been done in the past directly by manual labour but today is done by the tamping machine
The tamping machine works by vibrating the ballast and forcing it under the sleeper. These combined actions cause the ballast to form a close matrix which can support the track effectively.
Matisa pioneered the design of the first tamping machine in 1945. This original machine was totally mechanical with screws providing the in and out movement of the tools and a cam mechanism providing the vibration. It was known as the Standard Tamper.
The basic principle remains the same but the functions are often provided by hydraulics.
This is a Standard Tamper in Australia.
As I remember them, Standard Tampers were more enclosed but maybe this model was made specially for the warmer climate.
The man at the controls was a fitter that I met at the Adelaide depot and became a friend of mine.
Here he is seated in the travelling position at the rear of the machine, where he could see to drive in both directions.
The operator is now seated in the working position where there was an excellent view during tamping.
The tamping arms, actuating screws, eccentric bearings for vibration and the flywheels can be seen
This is a view of the Standard Tamper from the operating position.
Note the very comfortable seat!
The operating levers can be seen at each side.
"The Matisa Light tamper BL-09 M"
After the Standard tamper there were a succession of heavy tamping machines employing a variety of methods of tamping, but all adhering to the basics of pressure and vibration to move the ballast. And these machines were made in a variety of wheel gauges and modified where required for local conditions.
It became apparent that there was a need for a smaller and cheaper machine for small jobs. And so the Light Tamper was born.
We made a considerable number in our Chertsey, UK, factory from about 1956 Starting with our parent company's drawings (metric units and French text) we had to convert to Imperial measurement and source components in the UK as far as possible. Steel and other specifications had to be carefully looked into, but we got there in the end.
The Light Tamper was intended for working in small sites, such as marshalling yards, although it could also be used anywhere where speed of operation was not the prime consideration.
It started as two separate tamping heads on a trolley that was pushed by two operators, but was later used with a motorised trolley.
The machine was powered by two diesel or petrol engines, one for each tamping head, but one was also used to provide traction
Note the drive to the belt-driven eccentric flywheel that imparted vibration to the tamping heads. And the hydraulic traction motor.
The Light Tamper could be used on secondary track and off-tracked when necessary.
We did a lot of designing and manufacture at the Chertsey, UK, factory, including the 'JackPak'. This was a tamping machine designed for high lifting, such as in laying or relaying track.
The tamping heads were based on the proven Light Tamper heads and it would run in either direction at about 20MPH. Hydraulic power controlled by electronics was used throughout.
I do believe that's me, over 50 years ago, testing the JackPak on our works track.
That track took a hammering!
This view clearly shows the sleepers being lifted clear of the ballast while the vibrating tools force the ballast up under the sleeper being processed. The machine was capable of much higher lifts than shown.
Levelling of the track was taken care of by the large oil-damped pendulum at the front of the machine, and a telescope could be used on the targets at the front of the machine to ensure a constant height.
Later tamping machines combined lifting, levelling and aligning functions to enable track to be set geometrically correct before tamping. Of course it still needed human intelligence to programme the machine.