There currently does not exist in industry a reliable method for the detection of rail foot flaws. Like their head-based counterparts, foot flaws result in broken rail with potentially catastrophic consequences. A proposed area of research for the detection of these flaws is thermography, a non-contact method of measuring and analysing infrared emissions from an object under test. In industry, active excitation thermography is the most common, requiring an excitation source. This paper will present a temperature measurement system and a method of transient temperature extraction from the running rails for the effects of a passing train to evaluate heat transfer in the practical rail environment. The outcomes of these results will provide future direction in the development of a rail heat transfer model and determine if train passage provides enough active excitation for a thermography-based detection technique.