This document is a seminar report on vacuum braking systems submitted by Mohammed Shahbaz Hussain. It provides an introduction to how braking systems work by converting kinetic energy to heat. It then discusses the history and components of vacuum braking systems such as the driver's brake valve, exhauster, brake blocks, and brake cylinders. The working of vacuum braking systems is explained, from how applying the brakes causes a loss of vacuum to apply the brakes, and releasing the brakes restores vacuum. Advantages like safety and reliability are discussed as well as limitations such as requiring large cylinders. The conclusion compares vacuum brakes to air brakes and notes vacuum brakes were simpler for steam locomotives.