if gap is not left between railroads, it will expand in summer and will bend if no space is left

Railroads

Serfs were slaves who were owned by nobles.

the construction of railroads (from studyisland)

Robert Carmichael-Smyth has written:

'The employment of the people and the capital of Great Britain in her own colonies, at the same time assisting emigration and penal arrangements by undertaking a great national work' -- subject(s): Railroads, Colonies, Transportation

'The employment of the people and the capital of Great Britain in her own colonies' -- subject(s): Pacific railroads, Early projects, Railroads, Description and travel