**7. Conclusions**

Nowadays, railways are one of the most used mass transportation systems worldwide. Compared to air travel or car, their high transportation capacity and low environmental impact are significant advantages. Higher passenger numbers will be achieved by increasing those vehicles' attractiveness, which depends mainly on comfortable journeys. Passengers define a comfortable journey based on comfort, safety, and user conditions. Seat comfort is characterized by the interaction between seat dynamic and static characteristics. The former is associated with seat behavior under vibration conditions, whilst the latter concerns comfort evaluation in the absence of vibration. Therefore, both evaluation types should be performed to evaluate users' comfort properly.

The rail-wheel interaction associated with motion leads to a complex vibration environment. Besides affecting comfort, vibration is strongly connected to safety. Based on that assumption, a new CBM methodology capable of identifying train and rail maintenance needs was proposed. Following ISO 2631 approach, ride comfort was calculated for 18 journeys conducted on Pendolino, Intercity and Urban trains connecting Porto–Aveiro stations. Results matched those of IP obtained by the EM 120 inspection vehicle. The low-cost system was then validated, and its high precision was proved.

Improving the seating capability to absorb vibration is crucial to increasing passenger comfort. The extent to which vibration is amplified or attenuated depends primarily on the dynamic properties of the seat. Transmissibility quantifies these properties. Therefore, transmissibility tests were performed on comfort and tourist seats on the Pendolino train. The prominent transmissibility peaks were lower than those obtained for the simplified seat version in the laboratory experiments.

After classifying seat dynamic characteristics, the seat static parameters were evaluated by pressure tests. Maximum pressures were obtained at the discomfort threshold near the ischial tuberosities. Apart from this location, the pressure was equally distributed on the seat surface.

To the author's knowledge, this is a pioneering study considering a complete passenger comfort evaluation. Moreover, new low-cost and non-disruptive maintenance identification methodologies were proposed based on the passengers' comfort evaluation. The results of this research can be applied to improve users' comfort levels and increase the attractiveness of the rail mode of transportation.
