How does your submission match the theme?
My submission matches the theme of "Dual Purpose Design" as follows:

Changing tracks changes your speed and helps you avoid obstacles

Movement keys (Up and Down, W and S) change placement, increase speed when changing tracks, and reduce speed when pressing against a wall
Speed is both movement speed and a measure of health
Death penalizes you by making you restart the level, but benefits you by increasing your initial speed

Third-party resources
Code: Python and Pygame libraries

Art: GIMP image editor

Contributors
Music: "Furious Freak" Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
http://creativecommons.org/licenses/by/3.0/

Sound: (Both were trimmed using online-convert.com, with no further alterations.)

Minecart Clack: "passing train,trains paris #9" arnaud coutancier

Licensed under Creative Commons: By Attribution 3.0 License

http://creativecommons.org/licenses/by/3.0/

Minecart Grind: "Metal Scraping" Doctor_Jekyll

Licensed under Creative Commons: By Attribution 3.0 License

http://creativecommons.org/licenses/by/3.0/

Code: Built using Python, Pygame, and a personal GUI library. All game code is my own.

Art: All art made by me using GIMP

Thanks to Turncoda for playtesting!

Source Code
https://drive.google.com/open?id=0B6Q5QsTgdrccY2N1WktpMUM0VG8 (Excluding Pygame)