Automatic Pressure Modification ( APM ) de [ Automatic Pressure Modification ( APM ) device for KNORR BREMSE Design BMBS. Drawing No.: KBI Part No. I. 3. 5114. Material and Specification: As per drawing and conforming to RDSO, s Spec No. WD23- BMBS- 2008 ( Rev. 1 ) with Amend. No.- 1 of Sept. 2016 ]