Industrializing a Setting

[Coidzor]

The Eversoaking Sponge is not in Sandstorm. From what I can gather and recollect, it was in the Arms and Equipment Guide and featured in the Dry Spell adventure that WOTC released for free on their site ages ago.

It seems to absorb around 1,000 gallons per round and has a cap either of 225,000 gallons of water absorbed per day, or the same number is absorbed before it has to be wrung out and used to soak up more water.

[Fizban]

So you want to replace your magic trains with a portal network, a proper one where you go through one portal and end up at any destination. SBG gives the simplified version, but the Portal Master feat with that 50% discount comes from PGtF, and FRCS has much more detailed portal rules, which is where we got the super-discount 1/day portal.

FRCS does mention "Portals often come in pairs or networks." A portal with multiple destinations costs 25% more for each extra destination, which seems like a steal. The problem is, that doesn't upgrade the portal at the other end. For each portal you have to pay the +25% for each portal, exponential costs ahoy. The Portal Master market price for a network of portals that all link to each other is 50k+[12.5k*n]+[25k*(n+1)]+n*[12.5kn*+25k*n], where n+1 is the total number of destinations (for n+2 portals).

There are two ways to attempt reducing that price.

The first method uses a central variable portal, with return portals at each destination. This costs 50k+[12.5k*n]+[25k*(n+1)], and allows anyone at one of the destinations to reach the hub, then turn around and go to any other destination. Because portals always shunt past creatures there's no problem with crowding as long as there's enough open space. If you like the idea of a hub you can leave that as is, but personally I think a constantly swirling vortex of people trying to run back to the center is ugh, so instead one could use a much smaller handwave to turn them into a proper network from there- either people don't materialize at the hub at all, or they do so for only a brief moment before it sucks them back in. Problems with attacking the hub portal are obvious, but damage is somewhat limited in that all the destination portals remain unaffected.

The second is to deliberately read the portal rules wrong: they clearly state that a "two-way" portal is actually a one-way portal, with a second one-way portal that links back to the first created with a base cost of 25k instead of 50k. Instead of creating a second portal, simply deciding that a two-way portal is different and a variable two-way portal naturally links all destinations both ways, you get a price of 75k+(18.75k*n), which is dirt cheap. This version has a critical weakness in that by treating the whole thing as a single variable+returning portal, destroying one destroys the whole spidery thing.

Oh, and the portal key is simple, just set them to respond to the name of the destination on a piece of paper.

You could also just use a ring of portals, one at each destination in sequence and you just run the loop to get back to the start. Shutting down one portal cuts off the loop, and there's also a problem with adding new destinations. While you can (possibly) apply the normal rules for upgrading magic items to add more destinations to a hub or spider portal, adding a new portal to a loop is basically just going to cost more, since you either need to make two portals or add a variable to an existing part of the loop, you spend 125-200% of what you were initially spending. Still, this is the simplest and possibly most natural method, with the lowest cost of replacing any destroyed portals.


In addition to Teleportation Circle+Permanency, there's another spell that creates portals, or close enough: Create Crossroads and Backroad from Magic of Faerun (Druid 7). This has its own problems though, as in addition to a 3.5k experience point cost (nearly as much as a proper portal), it requires users to negotiate with the guardian, the guardian doesn't like urbanized areas, and if the guardian (an incorporeal creature with almost no offense and a 50' tether) dies that entry point is destroyed. Aside from the obvious mind crushing, low-level professional diplomancers could get people through without much trouble on an "oft-traveled" route, but the DC 25 you'd need for a "trade route" (hostile to indifferent) is gonna be much worse.

Both the detailed portal creation and crossroads/backroads rules are rather Forgotten Realms specific, but we've skipped another abusable item from back in the SBG: The Platform of Jaunting, Greater costs 76,500gp, allows anyone to steps on it to Teleport Without Error Greater Teleport anywhere they want. And that's it, no pretense of limitation like with a portal. Build one of those at each material plane destination and you don't need to involve portal math since they already go anywhere, at the slight cost of swiss cheese'd security for literally everywhere that isn't dimensionally warded. It's actually a bit more expensive than the minimum formula would have it, at 9th*17th*2,000gp/4 for wondrous architecture/magic trap.

For transporting goods alone across planar boundaries, I should have checked Planar Handbook before now: Ring Gates, Planar are exactly that. Unlike the basic DMG Ring Gates which only move 100lbs per day, these move up to 10,000lbs per day. That's 5 tons per day from point A to B for 200,000gp. You could link a few continuous portals for that cost, but you couldn't move them around and you'd need to distribute the load, or you could get a couple heavy transports for that cost, but they wouldn't be instantaneous. Another solid option for part of the overall network.


We have a number of purely magical methods of transportation we could use in place of inventing steam trains, but unlike those trains which require only a small and relatively cheap power sources, these require much higher level casters and resources, so we need to determine distribution of high level casters. Well we already know that per city, but that begs the question: how many big cities are there anyway? If you're altering an existing setting you just look at the list of big enough cities, but the two big settings that come to mind don't really count, since Eberron already has magic trains and dragonmarks, while Forgotten Realms is full of high level NPCs that clearly refuse to enact industrialized plans and/or counter anyone else who does.

The Medieval Demographics Made Easy page I like seems to indicate that the number of sufficiently large cities, and thus sufficiently high level casters, will be quite small indeed. Much like the high level NPCs themselves, only one city is the biggest while each after that is smaller by an average of half. You'd need to game it by dividing the overall population into kingdoms of 3 million each to get the highest number of metropolises, out of which maybe 2/3 will have a single Cleric high enough level to create Portals. Stuff that can be produced in dnd large cities (min 12,000 pop, min 3 NPCs of 10th level for each class with a good chance of a 13th level rep) is much more reliable, as you can get several large cities from a large enough starting pop even without gaming the system.

For massive transit, without trains the lowest level option is Crawling/Sailing Strongholds, at CL 11, which can carry immense loads with ease but not so much people, and only go up to 10mph.

I wanted to do a comparison on the costs of portals or other magical transit vs Eberron's Lightning Rail Coaches, which cost a hefty 58,000gp on their own before the unknown price of conductor stones for the track and trailing coaches, but I have no idea how many active lightning rails there are in Eberron and I don't feel like digging to find out. Obviously anything less than 20-30mph isn't going to cut it in comparison, and it's essentially impossible to reach that with anything less than a ship using soarwood (from Eberron itself), or a dragon or other creature with a massive fly speed.


The best custom item I'd suggest would be in contrast to the Greater Platform of Jaunting, a Platform of Wind Walking. Shadow Walk goes at 50mph but has an imprecise landing point, requires you to physically walk, and involves mention of the shadow plane which is full of lethal undead. Wind Walk pushes you along with a magical wind at 60mph, allows you to land precisely where you desire, and only exposes you to material plane dangers along the route you travel. Obviously there's still plenty of downside compared to the train: can't have overnight trips, check bags, do other stuff while you travel, getting stranded much more problematic, vulnerable to winds, but the upside of any-time departure and double train speed is quite useful. There is still a problem with the Gaseous Form effect allowing infiltration, producing magically airtight seals or positive pressure is even more expensive than covering everywhere with Forbiddance (which is actually a bad idea since it will kill people), but you're a highly visible white cloud that moves very slowly and has no armor. Or we could just use some custom license to alter the effect again, and just have the item not allow that (producing a Wind Walk/Gaseous Form effect that simply lacks Gaseous Form's pass through narrow openings clause).

The formula price for a Platform of Wind Walking is 33,000gp, with a range of 240 miles (in 8 hours of travel, with some to spare) for anyone who uses it. Cuts 15 or more days off a trip compared to foot travel. As a 6th level spell they also don't require a metropolis to build, same CL 11 as the Crawling/Sailing Strongholds.

For unlimited personal transport over longer distances, a combination of portals between sufficient towns and networks of Wind Walk platforms is probably most effective, though again not neccesarily the most efficient without knowing how many trains they replace. Which will never be a direct comparison anyway, since trains move people and cargo, while magic has to split the two.


Going back to city size though, here's a thought: a continuous two-way portal is essentially a tunnel straight to another point. If you link two cities with a continuous portal, you've basically combined the two into a single city. Which would let you hack your city sizes, once enough time passed for everything to mix and benefit from the increased whateverness. Also, a circle of radius 240 miles at average 75 people per square mile has a population of 13.5 million, easily enough to support one and maybe two metropolises, even though we only need one large city to produce a single Platform of Air Walk that can reach from the center to the edge in a day. A quick eyeballing of the part of the Faerun map I'm somewhat familiar with seems to suggest that it would be child's play to link the major cities via portals and WWPs if anyone actually bothered.