1 | Imagine the world where sun would explode, and people would add engine to Earth as a planet and make it move on those engines from the Solar system. People would move underground, and given that no Sun is available during the trip of the entire planet to a new solar system, people created underground cities and underground subways. Some cities are outside, but specifically re-built so that people could live and work in them w/o the need to wear spacesuits. Buildings are either connected via underground tunnels (which is easier), or special reinforced skybridges. Every exit and entrance have emergency spacesuits.

Fascinating scenario! You've described a world where humanity has undertaken a monumental feat of survival and engineering. Let's set the scene in this unique, planet-wide spaceship Earth:

Underground, vast cities sprawl through former mine shafts and newly carved caverns. Bioluminescent plants and advanced lighting systems create an artificial day-night cycle. The surface is a network of massive engines and energy collectors, with some fortified cities rising like domes.

2 | add a mix of new york-style and Snowpiercer-like double width trains please

Certainly! I'll incorporate that into our evolving underground world.

Picture this: Vast caverns house a blend of towering structures reminiscent of New York skyscrapers, but adapted for the subterranean environment. Threading between these are wide, multi-level train tracks carrying sleek, double-width trains inspired by Snowpiercer's design. These trains serve as both transportation and mobile living spaces, connecting different parts of the underground metropolis.

The trains glide silently on advanced magnetic systems, their windows glowing with artificial sunlight. Platforms bustle with activity as people board and disembark, some heading to work in the cave-buildings, others continuing their journey through Earth's core.

3 | add New York-style subway stations - white and black

Excellent addition! Let's integrate those classic New York-style subway stations into our underground world.

Imagine this: Nestled between the towering cave-skyscrapers are subway stations that pay homage to New York's iconic design. The walls are lined with gleaming white tiles, accented with bold black trim and signage. The familiar mosaic station names are illuminated by energy-efficient LED lights, creating a stark contrast against the organic, bioluminescent glow of the cavern beyond.

These stations serve as hubs where the sleek, double-width trains dock. Commuters rush across black and white checkered floors, their footsteps echoing in the cavernous space. The blend of retro subway aesthetics with futuristic train design creates a unique, timeless atmosphere.

4 | make station look like more modern, utilitarian New York City-style subway stations. Trains should be double-width.

I understand. Let's refine our vision to focus on a more modern, utilitarian New York City-style subway station, while keeping the double-width trains. Here's an updated description:

Picture a spacious underground platform with clean, minimalist design. The walls are smooth concrete, punctuated by large, backlit digital displays showing train schedules and city information. Stainless steel support columns line the platform, their utilitarian design offset by strips of LED lighting.

The platform is wide to accommodate the double-width trains, which dominate the space with their sleek, futuristic design. These trains, twice the width of traditional subway cars, feature large windows and aerodynamic profiles. The station's lighting is bright and even, casting few shadows and creating a sense of openness despite being underground.

Signage is clear and abundant, with large, easy-to-read fonts in the classic white-on-black color scheme. Benches are simple and functional, made of durable materials to withstand high traffic.

5 | add some people in lightweight spacesuits coming to the train. They're a part of a construction crew that is building a yet another underground city and station.

Excellent idea! This addition will add a dynamic and realistic element to our underground world. Let's incorporate these construction crew members into our scene:

Imagine the modern, utilitarian subway platform we've described, now with an interesting mix of regular commuters and specialized workers. Among the crowd, you see a group of people in lightweight spacesuits - clearly designed for mobility and protection rather than deep space exploration.

These construction crew members are easily distinguishable by their suits, which are sleek and form-fitting, with reinforced joints and transparent helmets. The suits are adorned with company logos and safety markings. Some carry specialized tools and equipment, hinting at the complex work they're undertaking in expanding the underground network.

They move purposefully towards the double-width train, ready to board and head to their construction site where a new underground city and station are taking shape.

6 | lovely. Now show a huge dome=like structure for plants. It's so huge that trains moving in both directions on parallel tracks cross that dome as if they were going through a national park.

What an incredible vision! This massive biodome will be a stunning centerpiece in our underground world. Let's paint this picture:

Imagine an enormous cavern, so vast it seems to defy the constraints of being underground. The ceiling of this colossal space is a geodesic dome structure, illuminated by advanced artificial sunlight systems that mimic the full spectrum of natural daylight.

Inside this dome is a lush, thriving ecosystem - a true underground national park. Towering trees reach towards the artificial sky, their canopies spreading wide. Meadows of colorful flowers, winding streams, and even small lakes dot the landscape.

Cutting through this verdant expanse are two parallel elevated tracks. The sleek, double-width trains glide silently along these tracks in both directions, offering passengers breathtaking views of the subterranean paradise. The tracks are designed to blend with the environment as much as possible, supported by elegant pillars that double as vertical gardens.