Since 2003 Ukrainian railways have used KPP-5 intermediate elastic fastenings. These fastenings unlike their predecessors (for example, terminal-bolted fastenings (KB) widely used on railways), first of all, have fewer elements. The KPP-5 fastening does not include screw joints, which considerably increases the pressing force between rail and tie, and resistance to track displacement forces. This may lead to reduction of the total labour input for routine track maintenance due to cutback of track works needed for mounting terminal and insert bolts. The article deals with forecasting the operational life of PRP 3.2 (9mm depth) and PRP 3.2.1 pads (10mm depth). In engineering the operational life is a time interval (for the railway track – tonnage passed) during which the element fulfils its functions. One of the main reasons why the assembly unit KPP-5 fails is low pressing forces between rail and tie. It occurs due to many processes; among the basic ones is the changed characteristic of underrail pads. And the application of new types of pads – PRP 3.2 (9mm) and PRP 3.2.1. (10mm) may solve this problem.