Jag letar efter en novell som jag läste i en antologi på 70-talet och jag kommer ihåg att det var en ganska gammal bok vid den tiden.
"Schrödinger's Cat" , en novelette av Rudy Rucker , matchar din beskrivning. Om du inte spenderar tidsresor kunde du inte läsa den på 70-talet, i en antologi som var "en ganska gammal bok vid tiden", eftersom den först publicerades i Analog Science Fiction / Science Fact , 30 mars 1981 . Kan du kanske läsa den i Rucker 1983-samlingen 57: e Franz Kafka ? Är någon av dessa omslag kända?
PS Tack till OP för att påpeka att historien finns tillgänglig på författarens webbplats .
Innehåller någon ett slags rör inom vilken tid som går i omvänd. Han ställer den på golvet och syftar till ett leksakspår på det att springa in i röret.
Det är en Lego bil, inte ett tåg:
The twins had brought the little car, a bright red-yellow-blue mass of Lego blocks. On the top was a battery-run motor, with a cogwheel linked by a black plastic chain to a gear on the single front wheel.
Klara examined our "time-tunnel" with interest. The core of it was the shoe-box-sized vacuum chamber made of phase-mirrors. You could see in quite easily. The thick loops of the guiding-field wires arched over the box like croquet wickets.
I removed the rifle from its mount on one end of the lab-table, and waited while Ion got the car from the little girls.
Then, bustling a bit, he lined up his three women in chairs against the wall, and set the car down at one end of the table. I cleared my throat, preparatory to telling them what they might expect, but Ion shushed me.
"First let them see, and then we'll discuss it."
I taped an iron nail to the bottom of the Lego car, and dialed the guiding-field's power up to some hundred times the level we had used before. The Lego car made a pretty big test-particle.
När tåget är samma avstånd från röret som röret är långt uppträder ett dubbeltåg vid den andra änden, och de närmar sig varandra ansikte mot ansikte tills de passerar genom varandra på röret ingången.
In all frankness, I expected the experiment to be a failure. The car would roll up to the phase-mirror box, bump into the side and stop . . . nothing more. But I was wrong.
As the little car labored across the table towards the left end of the box, something happened at the right end. Seemingly out of no place, an identical Lego car pushed out of the right end of the tunnel and went chuffing on its way! "And there's one inside now, rolling left!" Klara exclaimed, leaning forward. She was right. For a few seconds there were three Lego cars on the table.
Car (1): The original car, still approaching the tunnel's left entrance. Car (2): The one moving in the tunnel, from right to left. Car (3): The new one moving away from the right end of the tunnel.
And then car (1) and car (2) met at the left-end mirror. They melted into each other . . . nose into nose, wheel into wheel, tail into tail. It was like watching a Rorschach ink-blot disappear into its central fold.
One of the twins squealed and ran to catch car (3) before it ran off the other end of the lab table. I took it from her and examined it closely. Car (3) appeared to be identical to car (1). We had already done this experiment with electrons and with small bullets . . . but one bullet or electron is much like another. Until now I had been unwilling to accept Ion's interpretation of our experiment. But it certainly looked as if car (3) really was car (1).
Då gör någon den igen, men den här gången, när det andra tåget dyker upp i röret, och de två är på väg mot varandra, tar han ut yttre tåget för att förhindra att det kommer in i röret, vilket skapar en paradox , för att se vad som händer.
Ion had conducted a third experiment. The car was to roll towards the tunnel while he watched both ends. His plan was to stop car (1) if car (3) appeared, and to let car (1) go if car (3) did not appear. This meant that a car would come out of the right end of the tunnel if and only if no car came out of the right end of the tunnel. Yes if and only if no.
Det omedelbara resultatet är hans huvud splittras i två,
Question: When Ion actually ran the experiment, did car (3) appear? Answer: Yes and no.
I closed the lab book and looked around the room. The scattered bits of Legos . . . how many?
"What happened, Ion? Did the car come out of the tunnel?"
"Yes," Ion said, raising his head from on top of his arms.
"No," Ion said, uncrossing his arms and raising up his other head from under the arms.
The two faces looked at me, each of them a bit translucent, a bit unreal. The two necks merged into his collar, making a solid, tubular letter "Y."
[. . . .]
"I'm in a mixed state, William. I ran the paradox. It had to come out both ways." He turned the switch to power-up the guiding-field. It was dangerous to be restarting it without a vacuum in the chamber.
Då fyra, upprepade tills huvudet är en myriad liten stilk och dödar honom.
There was a crash behind me. I whirled around. The time-tunnel was billowing smoke and the phase-mirrors had smashed into pieces. For a second I couldn't see Ion through the smoke, but then he came at me.
A tangle of twenty or a hundred thin necks writhed out of his open collar, and on the end of each tentacle-like neck rode a tiny grimacing head, and every little head was screaming at me in a terrible tiny voice. . . .
He dispersed completely after that. As different variants of Ion Stepanek split off into different universes, each corresponding head would shrink . . . get "farther away" . . and a copy of his body would split off with it, twisting and dwindling. I don't know how long it took; and I don't know how I could have seen it; I wish I could forget it. The horrible squid-bunch of necks, each little head screaming out something different . . . I hope he's really gone.