Nor did he remain a mere inactive spectator of the improvements in railway working which increasing experience from day to day suggested. He continued to contrive improvements in the locomotive, and to mature his invention of the carriage-brake. When examined before the Select Committee on Railways in 1841, his mind seems principally to have been impressed with the necessity which existed for adopting a system of self acting brakes; stating that, in his opinion, this was the most important arrangement that could be provided for increasing the safety of railway travelling. “I believe,” he said, “that if self-acting brakes were put upon every carriage, scarcely any accident could take place.” His plan consisted in employing the momentum of the running train to throw his proposed brakes into action, immediately on the moving power of the engine being checked. He would also have these brakes under the control of the guard, by means of a connecting line running along the whole length of the train, by which they should at once be thrown out of gear when necessary. At the same time he suggested, as an additional means of safety, that the signals of the line should be self-acting, and worked by the locomotives as they passed along the railway. He considered the adoption of this plan of so much importance, that, with a view to the public safety, he would even have it enforced upon railway companies by the legislature. At the same time he was of opinion that it was the interest of the companies themselves to adopt the plan, as it would save great tear and wear of engines, carriages, tenders, and brake-vans, besides greatly diminishing the risk of accidents upon railways. While before the same Committee, he took the opportunity of stating his views with reference to railway speed, about which wild ideas were then afloat—one gentleman of celebrity having publicly expressed the opinion that a speed of 100 miles an hour was practicable in railway travelling! Not many years had passed since George Stephenson had been pronounced insane for stating his conviction that 12 miles an hour could be performed by the locomotive; but now that he had established the fact, and greatly exceeded that speed, he was thought behind the age because he recommended the rate to be limited to 40 miles an hour. He said: “I do not like either 40 or 50 miles an hour upon any line—I think it is an unnecessary speed; and if there is danger upon a railway, it is high velocity that creates it. I should say no railway ought to exceed 40 miles an hour on the most favourable gradient; but upon a curved line the speed ought not to exceed 24 or 25 miles an hour.” He had, indeed, constructed for the Great Western Railway an engine capable of running 50 miles an hour with a load, and 80 miles without one. But he never was in favour of a hurricane speed of this sort, believing it could only be accomplished at an unnecessary increase both of danger and expense.