Mike,
sorry i didn't see this till joe PM,d me this afternoon. My heater measures 40 ohms on my Simpson 260. By my calculations, it should draw 360w at 120v. Hope that helps.
My temp. meter is at work. If you need a temp. reading, let me know and I will get it monday. The line voltage when this was built was 110-105 volts, so keep that in mind if the engine runs at a higher wattage than on the nameplate. I found years ago that 20v difference caused a lot of problems with my early 30's radios- I actually rewound a lot of power transformers for radios that I wanted to play for extended time periods. I'm not sure how much difference it makes on steam engines, but a variac set at 105v is a good idea for anything more than a short run. You probably already know all of this though!
doug