This is a level editor I built for Rail Shuffle. The user interface is a bit crude in a few places, but most of it should be easy to understand.
Everything is built from the blocks in the right column. The top three blocks represent the ground type (orange, gray or green). Click on one to change it. Most of the others are objects that you select over there and then place on the level map using the SPACE bar. Use backspace/delete to remove unwanted objects. Rail pieces and obstacles (rocks, cacti, etc.) need to be placed on empty ground, while carts and money bags have to be placed on top of a rail piece.
A "complete" level needs at least one cart, at least one hole and at least one money bag. It also needs some "flat" ground decorations (besides the cacti, crates, rock and tree stump). You don't place these yourself -- you just specify how many of each type there should be, and then they will get distributed randomly. Click on one to increase its counter (default zero, max 9).
Each cart has a litte white arrow on it, showing its initial direction. To set it, place the cursor above the cart and press 1, 2, 3 or 4 for up, down, left or right.
Finally, specify the maximum time (seconds) for the level, and also the minimum number of seconds the player needs to have left after completing the level, in order to qualify for a "great" score. Then you can click on the Test button to try the level out below.
Now, if you manage to solve your own custom-built level within the "great" time limit, the applet will give you an encoded string in the text field above, which you can save in some text document and Import into the editor if you want to use it again later, or e-mail to me if you think it's good enough to be included in a future update of the game.