Dr James J. Drumm developed the traction battery in the late 1920s and was supported by the Irish Government as a means of using the excess electricity generated by the Shannon hydroelectric scheme.

The units had a maximum operating range of 40 miles (64 km) as demonstrated by a test run to Portarlington in 1932.

[1] Several inaugural runs were held in late 1931 including a trip with President Cosgrave on 2 December 1931.

There were two fires in the battery chambers with arcing and considerable heat generated but only charring to the coach body.

This is reasonable as Cyril Fry the creator was a draughtsman at Inchicore Works where the units were designed and constructed and would have had access to such drawings.