cg_drawGun 0/"0" (for all weapons), if railgun on button "e" - you can create (edit q3config.cfg)
bind e "weapon 7; cg_drawgun 0"
Gun1 for other weapons(if it meant only for railgun):
bind r "weapon 8; cg_drawgun 1" etc...

If "question" meant from the server side - then don't know!

their question was for the server side settings not client side

i dont remember how e+config works, try and make a copy of default configuration then
remove 'start weapon' WP_railgun and any railgun section in the config?

You need to edit this part of the cfg, tell it what weapons you want in your inventory here:(Example shows starting game with all players having Gauntlet and Machine gun only.)

/* Weapons in your inventory
*
* WP_GAUNTLET
* WP_MACHINEGUN
* WP_SHOTGUN
* WP_GRENADE_LAUNCHER
* WP_ROCKET_LAUNCHER
* WP_LIGHTNING
* WP_RAILGUN
* WP_PLASMAGUN
* WP_BFG
* WP_GRAPPLING_HOOK
*
* WP_NONE
* WP_ALL
**/
Start Weapons = WP_GAUNTLET | WP_MACHINEGUN;

Then... you might like to remove the rail gun from spawning as a weapon in the map by editing this part of the cfg in the same way:
(change to WP_NONE; to have no weapons spawn in maps)

/* Map Weapons
*
* WP_MACHINEGUN
* WP_SHOTGUN
* WP_GRENADE_LAUNCHER
* WP_ROCKET_LAUNCHER
* WP_LIGHTNING
* WP_RAILGUN
* WP_PLASMAGUN
* WP_BFG
*
* WP_NONE
* WP_ALL
**/
Weapons = WP_ALL;

if edit default.cfg, can create folder quake3/baseq3/pack0/default.cfg (If I remember it right)