It seems that the speeds of some of our early steam locomotives are too low. According to Wikipedia (http://en.wikipedia.org/wiki/Planet_%28locomotive%29), a train (unfortunately of unspecified weight) hauled by the Planet locomotive completed the 56km (http://en.wikipedia.org/wiki/Liverpool_and_Manchester_Railway#Construction) between Liverpool and Manchester in 1 hour in November 1830 - in other words, an average speed of 56km/h. Its current top speed appears to be 45km/h. Might I suggest a top speed for this locomotive of 60km/h, and adjusting the pre-1840s locomotives accordingly?
40-45km/h seems more suited to the rocket, as it reached 29mph at Rainhill. I'd reduce the planet slightly e.g. 55km/h, or at least make it underpowered, to give some reason for the better locos which weren't that much quicker e.g. patentee.
The Planet and Patentee should be separated by power rather than speed: the Patentee was just a larger and more powerful version of the Planet, so intended to haul more weight at the same speed.