Complex sentence: They were one of the few classes light enough to be permitted on the wooden Barmouth Bridge; others were the GWR 2251 Class and the LMS Ivatt Class 2 2-6-0.
Split into simpler sentences: They were one of the few classes light enough to be permitted on the wooden Barmouth Bridge. Others were the GWR 2251 Class and the LMS Ivatt Class 2 2-6-0.