99456
Withdrawal began during World War I ; the class had long since been superseded by newer and more powerful engines , but they were ideally sized for private sidings and bush tramways , so many were sold rather than scrapped .
 World War I
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 World War I