Currently, we are in the process of making electric rail available in OpenTTD! Because this involves a lot of big changes, we are creating it outside of the main development. Therefore, it isn't included in the nightlies. But, no need to be sad, you can download the latest version of elrail here:

Warning: using 'elrail' can unrecoverable damage your savegame, which can't be loaded by any version of OpenTTD. Do not report bugs related to this. You have been warned!

Electric Rail - Binaries

If you find problems in it, please don't report them via the webpage, but send a mail to {mailto:celestar@openttd.org} or post them at the forum-topic. Please read the BUGS file before doing so.

Also, don't be shy to tell Celestar what a great job he did!