A pressurized lubrication system for turbomachinery includes a gravity rundown lubrication tank raised vertically above a turbomachinery train. The gravity rundown tank is typically designed to provide emergency fluid lubrication during shutdown if the main and standby lubrication pumps fail to operate. This invention describes a gravity rundown tank with additional novel function of providing higher pressure Accumulator action lubrication fluid to delay and prevent a shutdown trip of the turbomachinery. The gravity rundown tank with novel features can be a single tank with multiple functions, or a plurality of tanks utilizing gravity pressure to ensure emergency lubrication at rundown, and providing accumulator action delay pressure and flow when switching from main to standby lubrication pumps. This improvement in the state of the art leads to eliminating the need for conventional equipment such as Accumulators thus providing higher lubrication system reliability and minimizing cost and complexity.