<p> The pressure gradients for sphere trains in 1 in. and 2 in. pipes have been measured with water flowing past the stationary spheres at Reynolds numbers (based on pipe diameter) from to 4 - 105 , and sphere/pipe diameter ratios ranging from 0.486 - 0.84. Two dimensionless pressure ratios have been derived so that the experimental results obtained can be generalised to any pipe diameter with the above constraints on Reynolds number and diameter ratio. Drag coefficients have also been calculated from pressure drop measurements for the 0.84 diam. ratio spheres in· 1 in. pipe. These have been compared with McNoun's drag coefficient. </p> <p> The application of the results to predict pressure gradients for sphere trains in any pipe diameter has been illustrated. </p> / Thesis / Master of Engineering (MEngr)