Everyone loves railguns but they have a major flaw: lag. Due to the complex nature of particle system calculations, railguns tend to lag a great deal when in mass numbers and even alone the weapons can cause susbtantial amounts of slow downs.
[page=Editing the Rules]
Find your railgun system and look for the Perturbation coefficients. Set those values to zero to take out 90% of the system lag. Those values include nice effects but they add extra calculations that are not truly needed. Set the ParticlesPerCoord to something small like .05 and that also will decrease lag.
Now find your railgun particle and lower the MaxEC to something like 20. That reduces the amount of time the railgun has to be calculated.
There, now you have lagless railguns.
Additional Credits: DeeZires's Editing Guide
Additionally, this will work in Tiberian Sun and FireStorm.