Modelling 45T monoblock TTA tank wagons

[Western Star]

Here is a photo showing progress in constructing a JLTRT 7mm kit of a TTA, prototype wagon appears to have been built by Pickering of Wishaw.

 

 

My knowledge of the modern wagon is poor and so I hope that other RMWers can fill in some blanks, for example:-

 

a/ how does applying the air-brake cause the brake blocks to be applied to the wheels?  (what gets pulled / pushed?  what parts of the air-brake gear are not provided in the kit?)

 

b/ the kit provides wire to produce the safety loops for the four brake yokes and castings for the safety loops for the handbrake pull rod, also castings for the paired levers in the centre of the underframe.  What other safety loops exist on the prototype?  Any photos which show such items?

 

thank you Graham

Edited February 22, 2022 by Western Star

[jonhall]

obviously your handbrake arrangement is different, but this shows the functional components

[jonhall]

These show several different wagons, with differing variations of arrangements, but are to show the style of what happens underneath a TTA

 

Jon

[Western Star]

Nice photographs especially as the first few are of a Pickering build and that is the prototype for the kit.

 

Thank you.

[Western Star]

2 hours ago, jonhall said:

obviously your handbrake arrangement is different, but this shows the functional components....

Agreed in regard to the handbrake.  The drawing explains how the brake force is transferred from the inner to outer brake yoke at each end, I now understand how that linkage works.  Where I am at loss is the reason for four transverse levers arranged to work in pairs - where are the pivots for those levers?

 

regards, Graham

[jonhall]

2 hours ago, Western Star said:

Agreed in regard to the handbrake.  The drawing explains how the brake force is transferred from the inner to outer brake yoke at each end, I now understand how that linkage works.  Where I am at loss is the reason for four transverse levers arranged to work in pairs - where are the pivots for those levers?

 

regards, Graham

 

the bits i've highlighted in yellow? the outer upper leg is anchored to the wagon frame where i've pointed to in red, so if you pull the linkage from the middle of the wagon, the shoes are able to clasp the wheel, and the force is equalised between the two shoes.

 

 

J

[Western Star]

Apologies if my most recent pots is confusing / ambiguous.  Your annotations to the drawing are the parts of the design that I do understand (after seeing your drawing).  Referring to your drawing, the operation of the two transverse levers either side of the air-brake cylinder, and the way in which the brake force is appled to the longitudinal pull rods, is the design feature which confuses me.

 

Just where are those levers "pivotted"?

 

thank you and regards, Graham

[jonhall]

These two in yellow?

 

The brake cylinder pushes the bar in green. The Blue link is solid, so it holds the two arms together at a fixed distance apart, the Right Hand yellow arm is fixed but pivoting to the cylinder, so in effect when the green link is longer, the blue bar is a fixed length, meaning the two orange linkages are drawn together. The pink is a return spring to help the brakes come off.

Jon