Two research gaps were identified in block–wheel–rail temperature assessment. First, current studies are not combined with train dynamics, which are better descriptions of the block–wheel–rail working environment. Second, current studies cannot simulate long rail sections. This paper developed a block–wheel–rail temperature assessment model by following the finite element idea. Models were validated by comparing with ansys Finite Element models and measured data. Case studies were carried out by combining the temperature model with a Longitudinal Train Dynamics model. A full-service and an emergency brake simulation were carried out for a 150-wagon heavy haul train on a 5680 m long rail section. The results show that, due to brake force differences at different wagon positions, the maximum block and wheel temperature differences among individual wagons in the full-service brake simulation were 117.01 °C and 117.91 °C, respectively. This highlighted the contribution of introducing train dynamics into block–wheel–rail temperature assessment. Rail temperature increases caused by wheel–rail temperature differences and frictional heating were about 10.60 °C and 2.65 °C, respectively.