6051
They proposed not to leave behind a single rail , a single cross tie , a single railway station , a single blockhouse , a single bridge , or a single electricity pole .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: date, organization, person, geographical social political, national religious political, facility, cardinal, location, work of art, law, event, product, ordinal, percent, time, quantity, money, language 
Text: {0} 
Answer:
 None