Escape Room in Physics: Train Experiment

We are demonstrating an example how simple an experimental puzzle of an escape room in physics can be, indeed, experiments and puzzles of a 2-hours-escape room should take minutes rather than hours compared to a conventional experimental course for students in education. We have used a miniaturized train for the purpose of gamification in kinematics driving in a circle (radius r) on a rail road. To calculate the velocity, one uses simply v=l/t (l length; t time, v velocity) with length of distance of l=2·Pi·r. The entire puzzle is able to remember on childhood or early life, respectively. Nevertheless, the train experiment can be understood as substitution of a similar toy as well, however, a train on railroad is an equipment in nurseries and a famous topic in comics and animated cartoons touching a - hopefully - peaceful early lifetime. A possible extension by an error calculation is proposed and presented.