"Elementary readers will follow the sequence of the process taken to build an extension of a subway system, from the proposal, planning, tunnel digging, and construction of the train and tracks. A table of contents, glossary, further resources, and an index are included"--"Elementary readers will follow the sequence of the process taken to build an extension of a subway system, from the proposal, planning, tunnel digging, and construction of the train and tracks. A table of contents, glossary, further resources, and an index are included"--.