A few years ago, I purchased this kit from World Kougei
プラシリーズ Nゲージ TMC400A モーターカー 組立キット
world-kougei.com/SHOP/6044380.html
It's a mixed ABS resin / photo-etched parts kit. It didn't look too difficult to assemble.
I started by doing some research about the prototype and found quite a number of photos and videos online. I was immediately attracted by the Totetsu white/yellow/grey livery, photos are available here:
mcdb.sub.jp/forums/topic/fhi_tmc400a_43_東鉄_4012/
I also found a video showing operation with two locomotives, and several sets of headlights and alert lights flashing. I decided to try to reproduce that scene. 

That's what the kit looks like.

​I started by applying an undercoat of Tamiya 87044 Fine Surface Primer for plastic and metal (white), on the photo-etched and resin parts. That seemed to give a good result, but as I will describe later, during the assembly the paint started to peel off from the photo-etched parts. That has been a huge issue. I usually use Tamiya 87061 Metal Primer, which works very well, I should have sticked to this one for this project too.

​Gluing the parts was supposed to be easy, but proved very difficult at first. I tried Tamiya 87182 Extra Thin Cement, which didn't work at all. Of course the Tamiya Craft Bond works but it is very thick, very slow to dry and not very strong. I ended up using standard CA glue, which works well but is too fast, no time to adjust the parts... Next time I will try Tamiya 87137 Cement for ABS.

Painting white and grey worked quite well. I then looked for the perfect yellow for the project. I tried AK11046 Radiant Yellow, AK11047 Lemon Yellow and AK11049 Fluorescent Yellow from AK-Interactive. These bottles include dispensers and the paint is ready to use with a brush or airbrush. I decided to go with AK11047 Lemon Yellow.

​I cut, weathered and pasted small rectangles of AE03 Metal plate anti-slip 90 for the sides.
www.finemolds.co.jp/www/list/listetc.htm
That was not too difficult to make and this is a nice improvement to the model. However, this made attaching the side fences much more difficult as I had to drill new holes for them.

I then started to experiment with LEDs for the various headlights. The plan was to make a small DCC decoder with 5 LED outputs, and connected the LEDs to it. 0402 Warm White LEDs for the head and tail main lights. 0201 White LEDs for the side lights. Various 0402 orange LEDs for the alert lights. I installed a total of 12 LEDs, and ended up with an unmanageable web of wires... impossible to solder to the DCC decoder.
I then decided to make another PCB just to manage the connection to the LEDs. That proved a good idea, but the whole thing is still very difficult to assemble and very fragile. Not recommended.

This is a photo of the EM13 decoder connected to the motor.

Anyway, I pushed through and made it work. So I now have 3 PCBs in this tiny cabin. The EM13 for the motor, the self-made DCC decoder for the lights, and another PCB right below the roof for connecting the LEDs. That's very difficult to manage. As I fell in love with that locomotive, I am now planning to redo it (next month, next year, or next life).
- The motor decoder is not necessary, the locomotive does not run well at low speed anyway, it would require at least a flywheel and a keep-alive.
- I plan to redo the lamp DCC decoder to fit it right under the roof and solder most of the SMD LEDs directly on the PCB, using 3D-printed light pipes. That would hopefully make the wiring much more manageable.

This is the final result before installation. I have fitted a small SMD LED inside the signal. I'm happy with the result. The dots forming the digit are neat (although they are just 0.3mm in diameter).

I decided to 3D print shunting route indicators to test the capabilities of my 3D printer. I designed the 3D models in Autodesk Fusion 360.

These are the first results

Even the digit indicator printed nicely.

I wanted to try to design and 3D -print catenary poles. I particularly like the modern steel-pipe design, and the section of tracks below required poles with interesting shapes.

I've designed the poles in Fusion 360, then printed them on my Elegoo Mars 4 Ultra. It was not easy to get them right, but I like the result.

Installation and additional photos

The spectacle shop, step by step construction

Making the facade, step by step 

Lighting the staircase 

Making of the signboard

I have used a new process for the signboards of the Japan Post building.
The case has been 3D-printed. The light comes from a new type of COB LED light strip. It is very narrow (2.7mm), can be cut every four LEDs, and the LED density is very high (480 LEDs per meter). It can be purchased from AliExpress here:
www.aliexpress.com/item/1005003193200776.html

Photos of the detailing process of the JPost building. The window blinds and shutters have been 3D-printed.

The second floor of the JPost building is a kindergarten.

The top floor windows are made of a sheet of clear/light blue acrylic. The window frames have been painted, then pasted on a sheet or mirror-like tape.

Next up: the rooftop details.
The electrical cabinets are from Matsuri Models (matsuriyamodel.booth.pm). 

Quick test after a first coat of paint.

This is my first 3d-printed building. It has been printed in several parts.
​The front (facade):

The main body:

The floor and rooftop will be printed later.
First, quick test fit on the layout:

On the layout, I use an LED control system described here: https://shin-yukari.weebly.com/led-controller.html. It is based on Adafruit 12-Channel 16-bit PWM LED Driver modules spread all over the layout. They allow a central computer (a Raspberry Pi in my case) to control the hundreds of LEDs fitting the various buildings.
In addition, I needed a similar control box on my workbench. This is a description of the system I have designed.

It uses the same Adafruit module and exposes the 12 LED outputs on terminal blocks with push-in connection, suitable for temporary connection (no soldering required, no screw).

Here we see a building "under construction", with its wires attached to the control box.

I have designed the PCB in Autodesk Fusion 360. The system is based on an ESP32 microcontroller connected to the Adafruit module and to the various connectors and terminal blocks. The ESP32 exposes a web page used to individually set the brightness of each LED.

I have finally purchased a 3D printer. I chose the Elegoo Mars 4 Ultra 9k, along with their Mercury XS Bundle, including the washing and curing stations.
The Elegoo Mars 4 Ultra is a small printer, the maximum build volume is only 153.36 x 77.76 x 165mm, but the resolution is super high: 18μm (that's 0.018mm). This is suitable for me as I will only print small models, but I need them super detailed.
The photos below show the complete setup, and the very first print!

The roof is fitted with accessories that have been 3D-printed.

I built simple light boxes to simplify the lighting of the building.

These are the steps I have followed to install EM13, FR11 and FR12 decoders in the Kato 10-1564 "Sunrise Express". This is a custom install that requires modification of the light boards and soldering of (very small) wires directly to the decoders. No modification of the car's frame was required.

I've used etched 1:150 cute animal barriers that can be purchased here
https://neonnoirdesigns.booth.pm/items/5377423
​https://www.etsy.com/listing/1277143858/1150-scale-etched-animal-barriers
​Many designs are available. Look for the Neon Noir Designs shop on Booth.pm or Etsy.
Painting:

• Tamiya Metal Primer (No: 87061) as a base coat
• Airbrush Tamiya XF-2 (flat) white
• then dry brush X-15 (glossy) green to highlight the raised surfaces. 

Next up, the vertical signboard

The front signboard backlight is made of a piece of polyester scored at precisely spaced intervals to spread the light evenly.

Next to the school dance building is the Softbank building. It is based on the very popular Tomix 4051 Square building set (brown).
​https://www.tomytec.co.jp/tomix/products/n/4051.html