Happy New Year and welcome to 2017, and as promised in last week’s post I have a new product to share with you this week. Back in November of 2016 I posted about a replacement tender draw bar design for a Marklin 4-6-2, you can read the post here.
The locomotive, as pictured below, is tender powered and the link from the engine to the tender is sprung. This adds a visual softness to the acceleration and deceleration of the engine by helping to disguise any sudden movements when the locomotive starts and stops.
The original draw bar was badly damaged and so attempting to glue it together wasn’t very practical.
A new draw bar was drawn up and 3D printed in Shapeways Frosted Ultra Detail material.
The picture below shows the original springs fitted nicely into the new part. The raised strip on the left of the part is to stop the spring moving too far when the draw bar is under compression. The same detail’s on the right but it’s on the underside.
Test fitting the part went well, as you can see below. The system fits by locating the loop in the spring around the peg in the locomotive; there is a bolt in the tender which act in the same way. As the powered tender moves forward the springs compress untill the force matches the strength of the sprung steel. Then the engine starts to move.
With the loco body fitted there’s a nice close fit between the tender and engine, possibly a little better than the original draw bar as the new one is ever-so-slightly shorter. Also, because of the spring system, as the locomotive navigates a corner the gap opens up preventing the tender and engine from binding or locking up.
The draw bar also pivots at both ends. The bolt at the tender end is visible near the front of the tender. The other end pivots under the front of the cab.
The last thing to do was remove the new draw bar and paint it black. Once it had dried and been refitted the locomotive was ready for use.
The replacement Marklin 4-6-2 tender draw bar is available from Shapeways here.
Next week’s post will be about another new 3D printed part and I look forward to sharing it with you then.