4576
Introduced in January 1954 , the class comprised 251 locomotives , of which 53 were constructed at Swindon Works , and 198 at Crewe Works .
 Swindon Works, Crewe Works
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Swindon Works, Crewe Works