  We look into modeling fuel cell hybrid trains for the purpose of optimizing
their operation using convex optimization. Models and constraints necessary to
form a physically feasible yet convex problem are reviewed. This effort is
described as holistic due to the broad consideration of train speed, energy
management system, and battery thermals. The minimized objective is hydrogen
fuel consumption for a given target journey time. A novel battery thermal model
is proposed to aid with battery thermal management and thus preserve battery
lifetime. All models are derived in the space-domain which along constraint
relaxations guarantee a convex optimization problem. First-principle knowledge
and real-world data justify the suitableness of the proposed models for the
intended optimization problem.
