Over more than 150 year, Finnish railway history has experienced important developments. Railway stations have seen and experienced many kinds of life. The value of stations changed if the station became busier or quieter. Photographs of all the stations and the history of stations are fairly well documented. The role of railway station clocks is different, even though they provide an important function. The thesis is based on an inventory of the extent and location of original triangular platform clocks in present railway stations in Finland. The inventory is based on old and new photographs, file materials, and interviews. The research result is dependent on the number of photos available and their quality, so this thesis will not manage to prove the original extent of the clocks. It is possible that the platform clocks have been moved from one station to another at some time, which has an influence on the result of this research. In addition to the inventory, this research deals with history of the Finnish Railway and model of railway platform clocks. The result of this inventory is dramatic, although this thesis cannot prove conclusively the extent of original triangular platform clocks. Now is the time to make the value of platform clocks known and encourage discussion about the retention of old platform clocks. This thesis is the first step in the potential for further research.