DEVELOPMENT OF STREET RAILWAYS 
widespread than either, is a mixed type partaking of the 
characteristics of both. The comparative density of popula- 
tion in Massachusetts naturally brings the settled areas near 
one another, and the rapid growth of the suburbs of the 
larger cities has caused those roads which were originally 
purely. urban in their character to extend their lines into 
suburban districts and into neighboring towns. Consolidation 
of separately incorporated companies has also led to the 
establishment of roads of the mixed type. 
Recently a new form of consolidation has brought together 
into one operating company nearly all of the railways in the 
eastern and southeastern part of the state outside of Boston. 
The constituent companies retain their identity, but a common 
ownership of a majority of the stock of each has led to 
uniformity in methods of operation. As the roads so operated 
maintain their separate legal organization, they may still be 
placed in the different classes indicated. 
During the last twenty years the development of street 
railways in Massachusetts has been very rapid, and with the 
practical introduction of electricity as a motive power this 
growth has become especially marked. The practical opera- 
tion of street railways by electricity has been wholly worked 
out since 1888, the first stretch of electric road opened to 
travel in Massachusetts having been on the Lynn and Boston 
Street Railroad on July 2, 1888. This was followed by its use 
on the West End Street Railway, in Boston, on Feb. ı6, 
1889, and the first road to be exclusively operated by electric 
power, the Boston and Revere Electric Railway, was opened 
on Aug. ı2, 1889. The total street railway mileage of the 
state and the length of track operated by electricity and by 
horses at different periods is shown in the following table : 
ro