Currently working and was tested over a 16 hour period and kept near perfect time, may have gained 5 to 10 seconds. It may need a service to keep absolute perfect time, has sat idle for a while. 1948 Hamilton Railway Special, Grade 992B, Model 5, 21J, 16S, lever set, stem wind, 6 adjusts, double sunken dial, railway grade with date serial number 1019245. The 10k gold filled case is 50.6mm in diameter. Dial has quite a few cracks, very nice case with minor general wear.