List of "Unidentified" Portable engines. The UPxx coding has been used by the Road Locomotive Society to Catalogue Portable engines which on initial inspection had no clear serial number / identity visible, as often the 'brass plates had been removed/ stolen with other parts. Many have subsequently been identified by experts against surviving build records and numbers stamped on the remaining parts such as boiler nos., crank numbers or discovery of the serial number stamped on the machine body during cleaning or dismantling for repair. The UPxx number is NOT an official number stamped on engines it is just used to keep track of them and once the real identity is established owners usually fit a new replica serial number plate with the manufactures name and number on. There are about 120 su