Arnold

ECW trucks are ordinary styrene. You have to fool around with Reboxx
wheelsets to find the correct axle length for them. Paint/weather them
first, including the wheels, because once assembled you cannot pry them
open to remove the wheels without damaging the assembly. I use Tenax
cement to get them square and then apply 2-part epoxy for durability. I
think the Dalmans are their best looking truck, although the National
Type B isn't bad. But it's no longer needed since Proto2000 did those.

Whether they are correct for any Type 21 tank car is another question.
You must ascertain this for yourself from photos etc. No one can answer
a question like "Is this truck correct for this type of car" without doing a
lot of research on your behalf. I can tell you for certain they were not
used on ALL Type 21's but they may have been used on SOME.

Tim O'Connor