Most rail fans are specifically made to comply with customer specifications and the expected harshness of rolling stock railway environments. Others are simply upgraded versions of standard fans such as the Ecofit GRF single inlet forward curved centrifugal fan. The GRF was primarily designed for operating with HEPA filters for pharmaceutical applications and toxic environment filtration systems. It consists of a high power external rotor motor fitted in a standard single inlet scroll assembly. In order to provide extra stability for the ...