Class 37 Loco N gauge (motorised)

This is one of my rolling stock designs in my N gauge railway collection. This is designed from scratch and have incorporated considerable detail from stock images of British Class 37 Locomotive. There are 2 versions.

V1 is designed to incorporate two Japanese motorised units and is the simpler version for assembly. It is also works out a little more expensive.

V2 is designed to accept two inexpensive 12v 8mm diam motors that run in tandem. The motors have dual shafts with 2 worm gears driving 2 axles on both bogies and creates a loco with 4 driven axles.

V2.1 Chassis
This Chassis v2.1 has a new coupling design and makes installation much easier. The hook is in the chassis STL but prints separately. Fit the (uncut) 10mm spring to the chassis and the hook will push and click into position. See image.
Spring 10x1.4mm: AliExpress ref 1005004657694818

I'll add parts and instructions below. Video added.

I have printed on Elegoo Mars 5 using default light and 20sec first layer. Please see Chitubox screenshot for orientation and settings.

V1 Parts:-
a) Motor Unit - PlazaJapan Ref 4957265140339
b) Screws x4 - M1.2x3.6mm - Amazon Ref B0CLLGCYP1 (bogies)
c) Screws x2 - M2x8mm - Amazon Ref B0HM3RC1 (chassis)
d) Screws x2 - M2x4mm see ref above
e) Washers x6 - M2 see ref above
f) Nuts x2 - M2 see ref above
g) Bearing - 3x9x5mm Amazon Ref B09ST92QCC
h) Springs - 0.1mm wire x 1.4x10mm - ALiExpress Ref - 1005004657694818
i) Weights - Amazon Ref B0BRTS67P2

V1 Assembly:-
1) Cut spring (h) in half and insert one in each bogie coupling (see image).
2) Insert two M2 nuts (f) in to hex recess in top of printed bogies.
3) Insert bearings into chassis and make sure the print-in-place mounts are free to pivot.
4) Use 2 screws (c) and 4 washers (e) to secure bogies to chassis.
5) Remove 2 screws from motor unit (a) shown in image and use two new screws (b) to secure into the bogies.
6) Add the body to the chassis/bogie assembly and secure with 2 screws (d) and 2 washers (e)

V2 Parts:-
a) Motor - 8x16mm Micro Coreless 12v 1mm shaft - AliExpress Ref 1005004816821398
b) Copper Strip - 0.2x3mm x 6m - Amazon Ref B0C2BF9M9J
c) Screws x2 - M2x8mm - Amazon Ref B0HM3RC1 (chassis)
d) Screws x2 - M2x4mm - see ref above
e) Washers x6 - M2 - see ref above
f) Nuts x2 - M2 - see ref above
g) Bearing - 3x9x5mm Amazon Ref B09ST92QCC
h) Insulated Wire - Wrapping Wire 30AWG 0.1mm - Amazon Ref B07HF9212C
i) Worm Gear - 6mm diam 0.5mm modulus 1mm shaft - AliExpress Ref 1005004965420741
j) Insulated Metal Wheels - Pack of 10 - Ebay Ref 405390611914
k) Weights - Amazon Ref B0BRTS67P2

V2 Assembly:-
https://youtu.be/NxKAoijF1YQ
1) Cut spring (h) in half and insert one in each bogie coupling (see image).
2) Insert two M2 nuts (f) in to hex recess in top of printed bogies.
3) Solder Motor and 30mm copper strip with 30mm insulated wire using 30mm wire for each (see image)
4) Add worms gears to both ends of both motors and align ends with shaft.
5) Insert motor into bogie - push carefully into bogie from end opposite to coupling.
6) Insert copper strips into recesses on the inside of bogies. Bend copper to do this. (see image)
7) Dismantle wheels (j) and reassemble with printed gear.(see image)
8) Carefully insert axles into recesses where it is backed with copper.
9) Insert bearings into chassis and make sure the print-in-place mounts are free to pivot.
10) Use 2 screws (c) and 4 washers (e) to secure bogies to chassis.
11) Remove 2 screws from motor unit (a) shown in image and use two new screws (b) to secure into the bogies.
12) Add the body to the chassis/bogie assembly and secure with 2 screws (d) and 2 washers (e)