These Class X engines are the steam power on the meter gauge Nilgiri Mountain Railway. They are Swiss Loco & Machine Works designed, but there have been several built at Indian Railway’s Golden Rock Workshop in Tamil Nadu. The first Indian-built ones were in the 2010s. These 2 began in 2020.
Pretty fascinating 4 cylinder design. HP cylinders power the adhesion loco, LP cylinders power the rack loco, utilizing and Abt design rack.
Steve