Make each default car a separate list in memory

So the link strings don't just grow over time

tilde-train.py

@@ -339,7 +339,7 @@ for fname in glob.glob('/home/*/' + traincarFN):
     ##print "Cannot open " + fname # for debuggering purposes
 
 while len(cars) < max_cars:
-  cars.append(default_car) ## add default cars if train too short
+  cars.append([*default_car]) ## add copies of default cars if train too short
 
 shuffle(cars)
 cars = cars[0:max_cars]