diff --git a/PHI-CL/data.lua b/PHI-CL/data.lua
index 348fe80..820b8a8 100644
--- a/PHI-CL/data.lua
+++ b/PHI-CL/data.lua
@@ -952,7 +952,7 @@ if settings.startup['PHI-VP'].value then
         data.raw.technology['artillery-shell-speed-1'].unit.ingredients = {{'automation-science-pack', 1}, {'logistic-science-pack', 1}, {'military-science-pack', 1}, {'chemical-science-pack', 1}, {'utility-science-pack', 1}}
         data.raw.technology['artillery-shell-damage-1'].effects = nil
         data.raw.technology['artillery-shell-damage-1'].unit.ingredients = {{'automation-science-pack', 1}, {'logistic-science-pack', 1}, {'military-science-pack', 1}, {'chemical-science-pack', 1}, {'utility-science-pack', 1}}
-        data.raw.technology['railgun'].prerequisites = {'military-4', 'artillery'}
+        data.raw.technology['railgun'].prerequisites = {'military-4', 'artillery', 'production-science-pack'}
         data.raw.technology['railgun'].unit.ingredients = {{'automation-science-pack', 1}, {'logistic-science-pack', 1}, {'military-science-pack', 1}, {'chemical-science-pack', 1}, {'production-science-pack', 1}, {'utility-science-pack', 1}}
         data.raw.technology['railgun-damage-1'].effects = nil
         data.raw.technology['railgun-damage-1'].unit.ingredients = {{'automation-science-pack', 1}, {'logistic-science-pack', 1}, {'military-science-pack', 1}, {'chemical-science-pack', 1}, {'utility-science-pack', 1}}