Part 5 (1/2)

It was time to take a better look at tunnel nineteen.

Johansen wasn't around so I collared Hunter. As an afterthought I belted on my patrol pack as well and we went down to the Port Authority at the up-axis hub. Jocelyn Merral was Port Chief, a handsome woman in her fifties-iron-gray hair and a penetrating gaze. We asked her to shut down the tunnel so we could go over it with a fine-tooth comb. She didn't get upset, she just refused. It would be too disruptive to her operations. Tunnel nineteen had been shut down for maintenance and investigation already. The backlog had kept a s.h.i.+p overtime at the down-axis hub. Did I have any idea how much that cost? It wasn't going to happen again.

I couldn't just order it done. The Port Authority is its own police within its jurisdiction. I tried to reason with her. ”Ma'am, we are investigating a murder that involves the Isolationists and the smuggling of UN weapons to Wunderland. Surely the Port Authority is as interested in resolving this as we are.”

She spoke slowly and firmly. ”The Port Authority is not at all interested in shutting down transport tunnels at the casual whim of the ARM.”

”Casual whim” was the key phrase. What she meant was that if we wanted her cooperation we were going to have to supply more information. I didn't want to do that. The odds were long someone in the Port Authority was involved with the smugglers, and as one of a handful with command access to the trans.h.i.+p net Merral was high on the suspect list.

Instead, I tried bargaining. ”Look, we just need to inspect tunnel nineteen. Can that be done without shutting it down?”

”Certainly, I have just the thing.” I was startled by her ready agreement. Information is currency to me, dealing for it is second nature. Merral had just been concerned about the efficiency of her operation. I wasn't used to taking people at face value.

She ushered us out of her office. The gravity was about a twentieth of a G and the corridors had static fields in the floor to aid traction. Merral walked in effortless forty-foot strides. Hunter moved with easy feline grace. I kept unsticking myself and hitting my head on the ceiling before settling awkwardly back to the ground. They had the manners not to laugh too much.

We left the corridor and entered the hub itself, a vast s.p.a.ce full of container racks. I'd been in tunnel nineteen myself but there were no containers in it then. The files on the s.h.i.+pping system contained diagrams of the containers and the hubs but they gave no concept of the scale.

s.h.i.+pping containers are ten meters square and twenty long. The down-axis hub is a hollow cylinder, a klick across and half that deep. Eight rows of storage racks line the hub-twenty-four thousand containers in hundred-meter piles. From any given point inside the cylinder the floor slopes upwards at an impossible angle and the looming racks seem about to topple over. Eventually the floor becomes what common sense dictates is a wall with the rows of racks marching up it with no respect for the gentle but insistent one-twentieth G tug beneath your feet. Farther still the wall becomes a ceiling with the racks dangling from it like ma.s.sive swords of Damocles. Containers are moved simply by launching them from the rack sorters on gentle trajectories either to the docking hub at the center of the cylinder or one of the tunnel entrances around its edge. The empty s.p.a.ce in the middle of the cylinder was full of containers in free fall and I had to consciously keep myself from cringing as they flew overhead with quiet rushes of air.

I felt like a mouse in a warehouse, scampering to avoid being crushed by the frenetic, incomprehensible activity going on overhead.

Merral was watching me. ”Impressive, ay?” she asked.

”Impressive isn't the word. I can't believe you let those things go in free fall.”

She laughed. ”It looks like disaster in motion, doesn't it? Actually it's very safe. There are eight hundred sixty-one trajectories. Whenever one is in use, all the intersecting flight paths are locked out until the container is down and clear of its destination.”

I looked up at the graceful, ponderous, hundred-thousand-tonne aerial ballet. It wasn't that I doubted her, but it was hard to shake the feeling all those containers were going to fall on me as soon as G.o.d cut the strings.

Our destination was a cargo box, but this one had doors and large windows cut in the sides. Powerful lights were mounted flush with the walls. Jocelyn thumbed a door open and waved us in. ”We use this for troubleshooting and inspections. It carries everything we need, and we don't have to shut down a tunnel to use it.”

Inside the container was mostly empty s.p.a.ce. There were doors and windows in the floor and ceiling as well as the walls and all the surfaces were padded and well equipped with handholds. Strapdown chairs with mounts that locked into the handholds were set up beside the forward windows. A quarter of the bottom rear was given over to a series of cabinets that housed batteries, switches and various tool chests.

Beneath the forward window there was a spartan control board with a compact data terminal as well as various b.u.t.tons, gauges and comm gear. Beside it was a small keypad. I recognized it at once from the trans.h.i.+p operations manual. It was the container's s.h.i.+pping control panel, a duplicate of the one mounted on the outside.

I walked over and examined the panel. When Jocelyn joined me, I asked, ”This contains the trans.h.i.+p codes?”

”Not just the codes, everything about the s.h.i.+pment. The freight manifest, maximum and minimum allowable temperatures, power requirements, loading parameters, whether the container is pressure sealed, center of ma.s.s, priority level, customs codes, COD status and charges. Everything.” She tapped a few keys and cryptic data slid over the small screen inset on the panel. PRI, COD, KPA, BOT, and others along with numbers that didn't mean anything to me. I did recognize two codes. SRC and DST indicated the container's source and destination-both were rack addresses in the up-axis hub.

I tapped a few keys and managed to bring up the DST code. ”Can you set this up to go anywhere?” I asked Merral.

”Anywhere on Tiamat. The lockouts don't allow us to be loaded for an offworld destination. This container isn't vacc sealed. I'll set it for the outbound receiving racks at the down-axis hub with a routing override so we get tunnel nineteen. That'll take us right through Tiamat.”

It was better than I'd hoped for. ”Can you try TMU19J234C?” I asked.

She looked at me with the half accusing ”How do you know what that means?” look that's usually reserved for medical patients who show their doctor some basic piece of medical knowledge. Specialists hate it when you trespa.s.s on their specialty. It makes them less special. Nevertheless, she thumbed the pad to authorize the change and punched in the destination code. After a couple of seconds the screen displayed accepted, then reverted to DST: TMU19J234C.

”This transaction is now logged in the transport net, correct?” I asked.

Merral nodded, adjusting the restraining straps that held her in her seat. She motioned for me to do the same.

”Is there any way to circ.u.mvent that?” I asked, fumbling with the belts.

”How do you mean?”

”Can you enter destinations into this panel without having the system become aware of it.”

”It could be done. You'd have to block the scan transceiver and trick the panel into thinking it had transmitted the change and received a valid authorization verification. It wouldn't be easy, we use dynamic encryption. Why would you want to?” She reached over and helped me get buckled in.

”A smuggler might change an onworld destination for an offworld destination, or perhaps just make a s.h.i.+pment the system isn't aware of.”

”I see what you're getting at, but you misunderstand me. If you prevent the panel from talking to the net, the net will just ignore it. It won't get sent anywhere. There's a lot of ways to break the system, but once it's broken it won't work properly.”

”I don't follow.”

”Look, the system is vulnerable to tampering and there's no way to avoid that. Rather than try to make it tamper-proof we've made it fail-safe. Getting a container to move involves a series of steps, with our control procedures built into the chain. If any link is broken the system flashes us a trouble warning and won't move the container.”

”And the data in the panel itself is all self-encrypted so you need a Port Authority ident to change it, correct?”

Merral warmed to her topic. She obviously enjoyed having someone show an interest in her work. It probably didn't happen too often. ”Not quite. The source address is always locked so we can back-trace a s.h.i.+pment, n.o.body can change that. When the s.h.i.+pment arrives and is accepted, the destination address is copied to the source so the container can be sent out again. Manifest, COD charges and destination are set by the s.h.i.+pper and then locked when the PA verifies and seals the s.h.i.+pment. The user functions-like humidity, temperature and all that-can either be set and locked or left open at the s.h.i.+pper's discretion in case they need adjustment in transit.”

”So you can't change the source or the destination in transit unless you have a Port Authority ident.”

”Not even if you do have a PA ident. Once a setting is locked, it can't be changed until the receiver accepts the s.h.i.+pment and signs off with us. The system only lets that happen at the destination address.”

”What if you hacked it, opened the box and modified the software?”

”All you'd do is cause a self-encryption verification failure. The system would halt the container at the next control point and drop a trouble flag.”

”What if I supplied my own panel that allowed in-transit re-routing?”

”It still wouldn't work. Firstly, it would fail PA verification at the point of s.h.i.+pping. Second, the trans.h.i.+p net and the panel would disagree on the destination as soon as you modified it. The net would halt the container and you'd get another flag. It's fail-safe.”

Fail-safe. It's a one-word lie. Nothing built by humans is fail-safe. Iknew someone was playing games with the trans.h.i.+p net. What Merral was really telling me was that I needed to look for hackers in the net's high-level control software or corruption at the Port Authority itself. I didn't tell her that: she might be the one I was looking for.

Instead I offered a compliment. ”Sounds like you're pretty secure. I've seen banks with looser systems.”

I meant it too. I didn't mention that I'd seen banks with looser systems because I'd gone in to investigate the frauds that had occurred at them.

”You've got to understand, there are better than two million containers in the system. Every day we move thirty thousand of them through Tiamat. The cargo value in just one of those can get into the tens of millions of crowns. We can't just lose track of one.” There was pride in her voice. She was a hands-on technocrat and the trans.h.i.+p system was her baby.

The conversation was interrupted by the arrival of the conveyor crane. The rollers on the container rack slid us into the jaws of the waiting cradle. I felt like Captain Nemo being attacked by a giant squid. There was a clang as the locking dogs engaged and then we were on our way, swaying gently in the minuscule gravity field. The crane loaded us onto the roller rails at the end of our row of container racks. The cradle disconnected and the crane swung away. The rollers began spinning and our container moved off.

I watched out the windows like a kid on a train for the first time. There was a double jolt as we were loaded onto a sorter, then a gentle surge as we launched into free fall. I watched in fascination as we soared past the tops of the container racks. We spun slowly and I got a revolving view of the entire, bustling hub. To my surprise we didn't come within a hundred meters of another container. What looked like near misses from below were a trick of perspective. There was all sorts of room.

We reached the top of our parabola and began to descend. There was another surge as tunnel nineteen's container receiver pulled us in. We landed perfectly flat and I realized what the spin had been for-Maintain This End Up at All Times. The whole experience was exciting but vertigo inducing. I got my stomach back under control and looked over at Hunter. He had eschewed the human-sized observation chairs, choosing instead to curl up on top of a large tool bin that afforded him a convenient view and loosely belting himself in with some cargo straps. He looked completely at home, curse him.

I was clearly going to have to get more zero-gravity time if I was going to fit in on Tiamat.

The conveyors hummed and with a gentle swaying we slid into the yawning entrance of tunnel nineteen.