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Traffic through Class C starports?


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Good morning, All,

What would you suspect that the average traffic through a Class C starport would be? How many ships, of what size? Etc.

For the purposes of this question, assume the Class C starport is located on a world that bridges a rift, and is one of only two routes across the rift within the sector.

Thanks in advance for your time,
It bridges a rift, eh?

Well, assuming both sides of the rift have a decent amount of traffic, I'd say it could well see thousands of travellers per week, and tens of thousands of tons of freight per week, and may have an order of magnitude more of both.

Assuming there's 5000 travellers per week, and 50,000 tons of freight per week, I get about 20 ships per week -- but some of those ships are biig.

I used a JavaScript program I wrote years ago, which may or may not be right:

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Landing : 9 ships (7200 t)
600t : 3
800t : 3
1000t : 3
Passengers: 390
Freight : 1200 t

Orbiting : 11 ships (176000 t)
3000t : 3
3500t : 2
8000t : 2
10,500t : 1
26,000t : 1
31,500t : 1
76,000t : 1
Passengers: 4600
Freight : 49000 t

Downport Components:
Airstrips : 1 MCr 0.01
Parkbays : 1 MCr 0.1
Fuel (T) : 2880 MCr 28.8
Repair (T/y): 720 MCr 72
Build (T/y): 900 MCr 90

Shuttles (MCr 545): 7 x 100t, 1 x 1000t

Ortibal Components:
Shuttleports: 4 MCr 40
Berths (T) : 17600 MCr 17600
Fuel (T) : 44000 MCr 4400
Repair (T/y): 176000 MCr 17600
Build (T/y): 17600 MCr 17600</pre>[/QUOTE]How's that for a guesstimate?

My reasoning is that, for general purposes only, traffic can be rated on orders of magnitude: a 0 for sleepy ports with incidentals only, a 1 for backwater ports with tens of passengers and 00's of tons, a 2 for small ports with 00's of passengers and 000's of tons of freight, and so on.

I'd rate a C starport as a 1 or 2 normally, but that can be bumped up 1 or 2 more points due to extraordinary circumstances, such as being 1 parsec from a Very Important world, or being on the XBoat route, or being part of a rift bridge...
Originally posted by Baron Weiskircher the Preacher:
What is the Population and classification of the world?
Population is in the thousands (Pop=3), and it is not a Red or Amber-zoned world, if that's what you're asking.


Do you really think it'd be 5000 travellers a week and 50,000 tons of freight a week? I guess I hadn't thought of it that way, but that just seems... a lot.

Are your numbers based on your own personal system, or on GT Starports, or another Traveller product?

I don't know, Jason. Normally I would only compare the world with its most significant trading partner; however, in this case, it seems to have some attention from an entire sector, so I guess.

A lower value is also reasonable. So, how about 168 travellers and 1680 tons of freight? That's 1 traveller per hour, 24 per day. The starport could make do with a small downport with a dozen or so open-air landing pads.

But even if a big freighter passes through every other week, the numbers go up, and you'll have an orbital port.

The problem is that by sitting on a rift, you're funneling traffic through that you wouldn't otherwise. Hence I inflated the values.

I'm basing the numbers on my own system, whose numbers roughly work with the cargo rules in Book 2. Here's another very old JavaScript program that estimates traffic between a pair of systems:


Playing with it a bit yields ranges from around 10 to 60 travellers per week. Sound better?
I'm okay with anywhere from 50 to 500 passengers a week, which appears to mean 500 to 5000 tons of freight. That gives me some numbers I can build around.

I'm also going to play with your scripts a bit.

Thanks for the inspiration and the guidance,
The scripts are old. If you find a better way, please inform me. I'm always looking for improvements to make. The system-traffic ones were just screaming to be written.
Frankly, I would think that the quality of the Starport is pretty much directly related to the traffic it receives, simply because if you have more traffic, you have more demand, and more money which goes in to better facilities.

If this C Starport is truly a rift bridge, then for whatever reason, nobody is using it, or the Starport is just getting off the ground (the 1000's of people could be employees of a company developing the Starport, for example).

A rift bridge, in fact, I would think would be of even higher quality (since there really isn't anyplace else to go). Kind of like an oasis in the desert.

So, if you have traffic, you have a good starport and vice-a-versa.

Put me down with Whartung on this one. This world bridges a rift, is one of only two such bridges in the sector, and it only has a Class C starport?!!? Traffic = Good Port the vast majority of the time at least.

Without finagling things too much, I'd peg the world for a Class B at least because ships will want refined fuel for their rift crossing.

You can squint a little and make the Class C port fit, if your players don't scream too much that is. Make the Class C port the only one open to the general public. All the big shipping concerns have private ports in the outer system busy fueling and maintaining their ships and their ships alone. If you haven't signed on with one of the big boys, you have to use the pokey old Class C down on the planet.

In this manner the planet resembles a small town a few mile off an interstate. Loads of traffic roars by out on the I-80, very little actually visits the town proper. There's a couple of massive truck stops out there, but the locals fill up in town. Busses whiz by hourly, but only one a day visits the town. Megatons of freight rumble past too, but just a few parcels are picked up or delivered in town.

In this manner, the planet is a backwater in it's own system! That way the amount of traffic calling on the planet proper can be whatever you say it is.

Considering the vast quantities of passengers and cargo required to keep an international RW airport going, I would have thought that the figures mooted here are very low. Even relatively small airports have tens or hundreds of thousands of passengers passing through per year, and big ones in the tens of millions.

They need them to make a profit, which (IIRC) mostly depends on parking fees and concourse sales. With pop 3, there's not going to be much local business (or even workers - maybe a lot of automation and robot staff), so most income will be from passengers in transit.

The infrastructure for even a class C starport surely makes RW airports pale in comparison, so I would postulate at least 10 million passengers a year, or about 25,000 a day. Scary thought.
Maybe its a Class C trying to make enough money to work up to B then to C
I always envisioned the Class A as the final phase of the starport ,just like most large airports ,Except the starport does construction and or heavy repair of starships ,while most airports are minor repair ,very few if any start out world class international when first built ( Except for politicaly inspired ones)
Just throwing out my 2 CR worth
If the pop is that small it sounds like some other planet, or the imperium is underwriting the cost to get trade to itself or from itself or both
I also found this site from a link here a while back i like it a lot for Starport costs and trade
Im not sure how to make it clickable so you wil need to type it in
Looking back at real world history as a reference

It could be an old Corp starport that over time just survives by taking in corp/subsidised ships and the occasional freetrader.

Maybe a resource world is on the the other side and this is the closest port for jumping but there is nothing else worth peoples time.

Maybe this was the first point that was setup as the rift crossing and after the second was up and running it became a more popular/feasible port to use for crossing. This one is still functional but just not as profitable.

Could be also that this was orginally an old military crossing point and just never drew large numbers of people. Over time it grew from a scout base to a Class C port.

As for type of traffic and how much, I would need to look at some more information of the history (real or we create to fit) and what type of worlds/resources are on both sides and whom found/use the jump first.

Dave Chase
It may be just a C (no yards at all) and still have refined fuel.

I have come to feel yards and other services shouldn't be combined into one sum.

B ports all have system ship construction yards, as well as refined fuel. One can't assume either for a C port, but so long as it doesn't have both, it's still a C port, even if it can handle landing 5MTd of shipping on the pads....
I'm partly with the esteemed Mr Whipsnade on this one, in his analogy of the truckstop world as freighters move on by.

By your own words Flynn, its one of two routes across a gulf of sorts, [bridged by J-3+ better ships me is imagining from your post and the word rift]so maybe its not the primary one!

Now..a refresher!

First of all, C-class ports, gentlemen, offer unrefined fuel as a rule [GT making exception with this, as C+ ports having refined fuel, and plain C as being the old standard UF available.] This seems an easy rule to port over without making it a full B-class.

Secondly, They also offer major repair facilities [i.e. you can get drives overhauled, major components installed/ replaced etc here], which for a trans-rift route, it should as a jump off point, no argument.

Thirdly--the low population. As the possible secondary route, my thnking is its used either infrequently, or is used only by independent or small shipping lines, as opposed to a larger corporations shipping, i.e. a Tukera LIC line of sorts, hence the low population is explained by the minimum number of persons needed, sans any robotic help [and early robot labor begins at TL-7+, IIRC].
An alternative look is based on TL. If the system is TL8+ the C-class population maybe in all in an orbital facility entirely, and the planet is not even occupied, save as an R & R retreat, and isn't included on the one line UWP at all. Here, if you're writing the system up in detail, you can point this out, if that's an option to your adventure.

Fourth point, the size and amount of traffic..
I don't think te class of a starport relegates the amount of freight anymore--not after seeing OTU examples like Ridge [1210] A77A112-F Lo Ni Wa 514 Im/Libert/ Diaspora which is an A-class facility; has a population of 1; and sits as a bridge world along a J-3 rimwards gulf.

If we return to the premise of it being a secondary route, then the reduced numbers of freight and passengers makes sense.

That's my take on this.
As usual, YMMV. Have a great Game weekend guys!
What would you suspect that the average traffic through a Class C starport would be? How many ships, of what size? Etc.

For the purposes of this question, assume the Class C starport is located on a world that bridges a rift, and is one of only two routes across the rift within the sector.
(glancing briefly through the previous replies) well that would depend on how much trade is taking place. if the four subsectors around the rift-crossing ('bout the limit of non-subsidized transportation) are low-pop low-trade worlds it's not likely there will be significant traffic. if one side of the rift has high-pop industrial worlds and the other side has ag worlds then you might have a huge traffic flow. context dependent.
well, I am a long way from the coast. My local airport runs maybe 100 flights per day.

largest planes are 727, lets guess 75 passengers average for all flights.

That is 7500 passengers a day. Greater tucson is maybe 700,000 people. We also have severe problems drawing bussinesses to town becuase the airport is not enough traffic to support a bussiness with offices out of town.

That makes us a small backwater airport in a backwater area. There are other modes of transport that service our town. Add Train, passenger cars and Busses, and if this small back water port was the local starport we would service 35,000 passengers a day. ( roughly the total of people coming and going, plus passing through.) We wuld hardly qualify as a type D port on an out of the way world. A type C would would be roughly equivelant to Omaha. A large C, or a small B would be New York, and an A would be roughly the traffic of all airports and cargo ports on earth.

Even a C is going to have 100's of ships a day, if not more. Take Baltimore. How many cargo ships go through there a day? That is one out of 10 or 12 ports on one coast, on one continet, and we are WAY below the production capacity or consumption of a space faring socity 50 centuries old.

Just my thoughts, but every time this topic comes up, I feel you are several orders of magnitude low in estimates of traffic.

I do tend to be a bit of an iconoclast though.
Just a thought here - are airports and planes the right model to be using?

How do all those passengers afford the ticket prices?

As flykiller says, a lot will depend on how much trade is taking place, which varies from TU to TU.
IIRC, most airlines break even or make losses on passenger flights. Their profits rely on cargo-hauling. The OTU also seems more geared towards cargo than people transport.

Traveller ticket prices are clearly based on air travel in the 70's, so they are very expensive. With airlines, we have low prices now because of tax breaks and low-cost airlines.

I agree with Sigg that this may not be the best model for spaceports, but I can't think of a better one. The bottom line is, a spaceport has to make money. There are three options:

1: It handles enough trade
2: Passengers spend lots of money passing through
3: Government subsidy
Wouldn't traffic depend on local, i.e. subsector, population? Like in something like TNE's hubworlds, there are probably only several hundred ships in total (I'm not sure whether or not to include government vessels, though), so there wouldn't be as much traffic at a class-A port there.