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In 1972, RTC conducted a series of tests to evaluate the effect on tamping on the track lateral resistance. Their results, published in 1973, have been referenced in numerous other research documents, including the ERRI D202 Reports – the committee that produced UIC Leaflet 720R “Laying and Maintenance of CWR Track”.

The main conclusion of the report is that on the test site, tamping caused a 37% reduction in the value of maximum resistance, dependent on the lift applied during tamping. After 1.3 million tonnes of traffic, a regain of resistance of 93% was achieved.

TN-SM-123-The effect of tamping and of subsequent traffic on lateral ballast resistance – Brentwood site tests (Michaeld C. Powel, RTC Derby, 1973).