Complex sentence: The boilers were fed by mechanical stokers using coal known as Shaw slack with a calorific value of 12,963 Btu/lb. During two days of testing the engine developed power of 1089.7 and 1049.4.
Split into simpler sentences: The boilers were fed by mechanical stokers that used coal known as Shaw slack. This has a calorific value of 12,963 Btu/lb. During the two days of the test the engine developed power of 1089.7 and 1049.4.