diff --git a/90_Tower/lua/train.lua b/90_Tower/lua/tower.lua
similarity index 97%
rename from 90_Tower/lua/train.lua
rename to 90_Tower/lua/tower.lua
index c5e07b76..b86539a4 100644
--- a/90_Tower/lua/train.lua
+++ b/90_Tower/lua/tower.lua
@@ -6,10 +6,10 @@ CREATIVE COMPUTING  MORRISTOWN, NEW JERSY
 
 ]]
 
-local MAX_DISKS = 7 --"<const>" can be used starting in Lua 5.4, as such: "local MAX_DISKS <const> = 7"
-local MAX_DISK_SIZE = 15
-local MAX_MOVES = 128
-local NUM_TOWERS = 3
+local MAX_DISKS <const> = 7
+local MAX_DISK_SIZE <const> = 15
+local MAX_MOVES <const> = 128
+local NUM_TOWERS <const> = 3
 
 local towers = {
     { size = 0, elem = {} },
diff --git a/91_Train/lua/train.lua b/91_Train/lua/train.lua
index 0d11e73c..dde7cd4d 100644
--- a/91_Train/lua/train.lua
+++ b/91_Train/lua/train.lua
@@ -8,12 +8,12 @@ print [[
 
 math.randomseed(os.time())
 
-local error_margin = 5.0
+local ERROR_MARGIN <const> = 5.0
 
 function play()
-    local car_speed = math.random(40, 65)
-    local delta_time = math.random(5, 20)
-    local train_speed = math.random(20, 39)
+    local car_speed = math.random(40, 65) --Between 40 and 64
+    local delta_time = math.random(5, 20) --Between 5 and 19
+    local train_speed = math.random(20, 39) --Between 20 and 38
 
     print( string.format("\nA CAR TRAVELING AT %u MPH CAN MAKE A CERTAIN TRIP IN %u HOURS LESS THAN A TRAIN TRAVELING AT %u MPH.", car_speed, delta_time, train_speed) )
 
@@ -33,7 +33,7 @@ function play()
     local car_time = delta_time * train_speed / (car_speed - train_speed)
     local percent = ( math.abs(car_time-input) * 100 / car_time + .5)
 
-    if percent > error_margin then
+    if percent > ERROR_MARGIN then
         print( string.format("SORRY. YOU WERE OFF BY %f PERCENT.", percent) )
     else
         print( string.format("GOOD! ANSWER WITHIN %f PERCENT.", percent) )