Sydney Train Game Solver

What are the rules of the Sydney Train Game?

The way I've chosen to define the train game is as follows:

• You are given four integers (the carriage code)
• You may use any bracketing and +-*/ as you wish
• You must keep the same order
• You must only use each digit once

Can you form an expression that evaluates to 10?

It is solvable approximately 70% of the time.