Tokyo Metro has developed a special bogie (PQ* monitoring bogie) that can monitor the forces between wheels and rails and derailment coefficients on the service line. At the same time, in service lines with sharp curves, Tokyo Metro has also introduced a steering bogie that directs the wheelset in the radial direction of the curve with linking the bolster and axle box. And to modify this steering bogie into a PQ monitoring bogie, we performed simulations and various actual vehicle tests. This study reports the results of these developing tests and practical applications. PQ*: In Japan, character “P” means the character “V” (Vertical Force) and character “Q” means the character “L” (lateral Force) in general. Then derailment coefficient L/V means Q/P in Japan.