Lua error in Module:WikiProject_banner/templatepage at line 315: too many expensive function calls.

Backtrace:

(tail call): ?
[C]: in function "error"
MWServer.lua:81: ?
(tail call): ?
Module:WikiProject_banner/templatepage:315: in function "check_cat"
Module:WikiProject_banner/templatepage:328: in function "check_assessment_categories"
Module:WikiProject_banner/templatepage:399: ?
(tail call): ?
(tail call): ?
mw.lua:527: ?
(tail call): ?
[C]: in function "xpcall"
MWServer.lua:99: in function "handleCall"
MWServer.lua:313: in function "dispatch"
MWServer.lua:52: in function "execute"
mw_main.lua:7: in main chunk
[C]: ?

Template:WikiProject Trains