Electric was a very peculiar system in use at RAL. In its first version its files were accessed remotely (from MSSL terminals) with a curious one-way line-editor (one could edit a file in the forward direction only, one had to close and restart to go back to earlier lines). Later files were kept on the MSSL PDP, and sent via a RJE link.

The files were full JCL jobs, inclusive of Job Control cards, the full Fortran source, and eventually data.
A peculiarity was that all files were double. The primary file could make parametric references, and a secondary control file defined combinations of possible parameter values. Thus one could invoke a job with a particular parameter set, and alter the program behaviour.