Consider the following network:
this would be represented as a simple text file:
1 2 3 2 3 5 1 4 6 1 3 2 4 3 1.5 4 5 6 3 5 4
Per row, the first term is the source node, the second term is the destination node, and the third term is the upper bound for a $Uniform(a,b)$ distribution. For instance, the distribution for the a13 arc should be $Uniform(0,2)$. The largest numbered node in the second column (over all the nodes in the network) may always be considered the terminal node and node 1 will always be the single source node of the network.