First-passage percolation on ladder-like graphs with heterogeneous   exponential times
  We determine the asymptotic speed of the first-passage percolation process on some ladder-like graphs (or width-2 stretches) when the times associated with different edges are independent and exponentially distributed but not necessarily all with the same mean. The method uses a particular Markov chain associated with the first-passage percolation process and properties of its stationary distribution. 
Henrik Renlund
math.PR