Let us to build Nerissa Gliders between Manchester and Liverpool to explore all options as an example of green and environmental machine. Manchester is 125.00metres over sea level and Liverpool is 70.00metres over sea level. This makes Manchester higher by 125.00 – 70.00 = 55.00metres than Liverpool. The distance between both points is 52.00Km from centre to centre. One option is to build it a long existing railway lines. This option should reduce the cost of fuel and wear and tear caused by unloaded major components and it should reduce travel time. For an assumed acceleration of 0.25m/s/s, it shouldn't take more than 15.00minutes.
Another option is to build a route along the existing railways but on an even level. In that case, we have to build the station in Liverpool 55.00metre high and outside the city. So passengers and cargoes in Liverpool have to go up 55.00metre, which produce CO2 and have a fuel cost but most of this cost can be recovered. Because potential energies of the vehicles take up passengers and cargoes can be recovered and the potential energy of what ever comes from Manchester can be recovered too. Because the gliders are travelling on an even level, they need a minimum amount of energy to run. The potential energy of cargoes and passengers coming from Manchester could be quite more than enough to run the gliders on both directions. With a few windmills build a long the route, we should have energy enough to run the gliders at any weather conditions at their usual speed. On the other thought, because Liverpool is on the sea, where wind power always available, windmills can be build near the sea to supply power to Nerissa Gliders Shuttling between Manchester and Liverpool.
Alternatively, we can build it between both points to depend on gravity power mainly. This is assuming we can get a straight or nearly straight route between both points. The stations has to be built outside the cities with an assumption distance of 40.00km or 40,000.00metres between both points. To get a gradient or a slope sharp enough for gravity, we use a height of at least 200.00metres in Manchester. But in Liverpool, we use the same height of 55.00metres to keep the even level route from Liverpool to Manchester.
The Gliders from Liverpool to Manchester move on an even level route. So they don't need a lot of energy. Cargoes and passengers in Liverpool go up 55.00metres in vehicles. This cost fuel and create CO2 over 55.00metres. But potential energy of vehicles going up can be recovered, when they come down, and stored for reuse later. In Manchester, cargoes and passengers have to go up 200.00metres, which cost fuel and create CO2. But potential energy of vehicles going up can be recovered, when they come down, and stored for reuse later.
The gross weight potential energy of gliders from Manchester to Liverpool can be recovered and stored for reuse later. Potential energy of cargoes and passengers coming from Manchester can be recovered at Liverpool station when they descent 55.00metres. The total energy recovered and stored should be more than enough to drive gliders from Liverpool to Manchester and lift up them 200.00metre in Manchester.
In this system, we operate a transportation system between Manchester and Liverpool possibly without any external energy input and with a negligible CO2 production. CO2 produced only on a route of 255.00metres, 200.00metre in Manchester and 55.00metre in Liverpool. But we eliminated CO2 production on 80,000metre route, 40,00.00metre per direction. Because the gliders don't carry major operating components, wear and tear almost become negligible. Accordingly no machine can be as green as and as environmental as Nerissa gliders.