Not all haulage was by horses, and an experiment was carried out on the Middlewich Branch of the Shropshire Union Canal in 1888. Following suggestions by Francis W. Webb, the Mechanical Engineer for the London and North Western Railway at Crewe Works, rails were laid along a stretch of the towpath near Worleston, and a small steam locomotive borrowed from Crewe Works was used to tow boats. The locomotive ran on gauge tracks, and was similar to "Pet", which is preserved in the National Railway Museum at York. It pulled trains of two and four boats at , and experiments were also tried with eight boats. The canal's engineer, G. R. Webb, produced a report on the expected costs of laying rails along the towpaths, but nothing more was heard of the project, and the advent of steam and diesel powered boats offered a much simpler solution. The 'mules' which assist ships through the locks of the Panama Canal are a modern example of the concept.