I tested out the 4-8-4 J steamer (number 613) after receiving it in the mail and was surprised at how quickly it accelerated. I only had the EZ-command speed gauge up around 2/5ths of the way, and the engine was already going as fast as the top speed of a Broadway Limited Commodore Vanderbilt, which I ran side by side for comparison. I understand the Js were known as the most powerful 4-8-4s built for passenger service, and that a J would want to travel fast, but for a scale model, I don't think there would have been much harm in decreasing its max speed, especially if you're like me and working with a small 4x8' space.