Yuliang Zhou
Graduate Research Assistant

Fabian Hansmann
Plasser & Theurer

Tamping is a vital maintenance activity to correct railroad track geometry by lifting, aligning, and levelling the track. Traditional tamping practices in the US are often rather empirical and rely heavily on operator’s experience. Railroads have learned that improper tamping parameters impact ballast stability and cause quick track geometry deterioration. Therefore, the purpose of this study is to investigate the correlation between tamping parameters and ballast performance. To achieve this objective, a series of field tamping tests were conducted on Norfolk Southern Railway's mainline, using a Plasser "Smart Tamper" capable of measuring numerous parameters during the tamping process. The tests involved different combinations of squeezing time and number of squeezes on both clean and fouled ballast sites. Additionally, "SmartRocks" were used to monitor ballast performance during and after the tamping process. These sensors recorded ballast particle motion and contact stresses, transmitting data in real-time through a remote-controlled Data Acquisition System (DAQ). Data analysis revealed that clean ballast had better performance in particle motion and bulk stress when using 1s squeezing time or 0.6s squeezing time with 2 squeezing numbers. Overall, the use of "Smart Tamper" and "SmartRocks" proved to be an effective tool for understanding the tamping process and optimizing tamping efficiency and quality.