Yes, that's right -- mandolins were all the rage from about 1894 to 1924.  Mandolin clubs popped up at high schools, colleges and cities all over the country.  The club at RPI evolved out of the Banjo and Guitar Club in 1892 --  it was called the Banjo, Guitar and Mandolin Club.

When mandolins outnumbered the other instruments it was renamed the Mandolin Club. The RPI club performed concerts on campus and at area churches. In later years, they performed along with the Glee Club. The performers were always presented in formal attire.

The height of popularity appears to be 1908-1909.  An article from 1908 stated that:

There has been a notable increase in the membership of the Rensselaer Polytechnic Institute Mandolin Club this year, several new men being secured from the junior and sophomore classes when rehearsals were commenced last fall, as well as from the incoming class.  So that while the strength and musical quality of the club has been improved there is every indication that it has become one of the permanent organizations of the Institute.

There were twenty-one students in the club that year and over half of them played the mandolin. The remaining members played guitar, violin or banjo. They also let in a flute player.  The number of members remained fairly stable until 1921.  The Mandolin Club became dormant around 1922.  Not so permanent, but a good run nonetheless.