I never understood why people disappeared from my life—until I learned about the "train theory" of relationships

I used to keep a quiet tally in my head of the people who weren’t in my life anymore. Not in an obsessive way — more like a mental list I couldn’t quite erase.

Friends I’d seen every week who suddenly weren’t returning my texts. Co-workers who I swore I’d keep in touch with after they changed jobs, but never did.

People I’d once known inside-out who now felt like strangers when I passed them in the grocery store.

It wasn’t always dramatic. Sometimes it happened with no conflict, no sharp ending, just a gentle fade. But those fades hurt too.

They made me wonder: Was it something I said? Did I miss some unspoken cue that I wasn’t wanted anymore?

One day, after yet another friendship quietly dissolved without explanation, I started Googling things like why do people stop talking to you — a true sign you’re deep in the spiral.

I stumbled across something called the “train theory of relationships,” and as cliché as it sounds, it was like a light switching on.

It didn’t erase the sting of loss, but it changed the way I saw it. Suddenly, I wasn’t taking every departure as a silent verdict on my worth. I could see my life — and the people in it — differently.

The train theory explained

Think of your life as a train journey. You’re the constant — the train itself, moving forward on the tracks.

Everyone you know? They’re passengers. They get on at different stations, ride with you for a while, and then — at some point — get off.

Some might only be with you for one short stop. A person you meet on vacation who you connect with instantly but never see again.

Others ride for years — childhood friends, long-term partners, mentors who guide you through key life stages.

A rare few stay on your train for almost the entire ride, changing seats when they need to, but sticking with you through storms and scenery changes alike.

When I first read this analogy, it hit me how much pressure I’d been putting on myself to keep everyone onboard forever. I was acting like the conductor who runs up and down the aisle, begging people not to leave, instead of just focusing on steering the train.

The train theory helped me see that when people get off, it’s usually not about me.

Sometimes their stop simply comes before mine. Their path veers in a different direction — a move to another city, a shift in priorities, a new season of life that doesn’t intersect with mine in the same way.

And just as importantly, I realized that I’ve gotten off other people’s trains, too. Not because I didn’t care, but because my own journey pulled me elsewhere.

Seeing that pattern from both sides made me more forgiving — not just toward others, but toward myself.

Here’s the other thing: when someone leaves, it opens up space on the train. A seat becomes available for someone new, someone whose timing and direction match where I’m headed now.

It’s not about replacing people. It’s about making peace with the natural ebb and flow of connection.

This shift didn’t happen overnight. But slowly, the departures hurt less, and I no longer felt the need to ruminate about every possible reason for them.

What I stopped doing once I understood

One of the most freeing changes I made after learning the train theory was letting go of the need to “fix” relationships that had naturally run their course.

Before, I would go into overdrive when I felt a friendship slipping — suggesting meetups, sending random check-ins, convincing myself that I could pull us back to what we once had if I just tried harder.

Now, I can recognize the signs without panicking. If someone’s energy changes, if conversations start feeling like a one-sided effort, I can take a breath and let it be. Not in a bitter way, but in a “your stop is coming up” way.

I also stopped attaching my self-worth to how many people were on my train at any given moment.

There were times when I looked around and realized my passenger list was pretty sparse. Before, that emptiness would’ve sent me into a quiet crisis — a feeling of failure, of being left behind.

Now I understand those quiet stretches as part of the rhythm. Sometimes the train needs to run light so it can pick up new passengers without being too crowded for them to settle in.

Perhaps the biggest shift was that I started giving people the freedom to leave without resentment — and giving myself that same freedom.

There are people I’ve loved deeply who I no longer have space for in my day-to-day life. Not because I stopped caring, but because we’re on different routes now.

When I frame it as “different destinations” rather than “someone abandoning me,” the goodbye feels softer.

There’s still grief. I’d be lying if I said otherwise. You can understand the train theory completely and still miss someone’s presence.

But now, I can hold that sadness alongside the gratitude of having shared the ride for as long as we did.

This perspective also changed how I approach the people who are with me. I’m less worried about how long they’ll stay and more focused on appreciating the view together while we have it. It’s a shift from clinging to savoring — from fear to presence.

Final thoughts

I used to think my job was to keep the train full at all times, to make sure no one ever felt they had a reason to get off.

But that’s not the point of the journey. Some people will only be there for a short ride; others will stay for years.

What matters is that you keep moving, keep making space, and keep trusting that the right people will show up at the right stops.

When I think about the friendships I’ve lost, I don’t feel the same heaviness anymore. I picture them stepping off onto a platform, waving, and disappearing into their own path.

I imagine the empty seat beside me, waiting for someone new — or maybe just giving me room to stretch out and enjoy the quiet for a while.

Life feels lighter when you stop fighting to keep every passenger onboard. You realize you don’t have to chase after the ones who leave — because your train is still moving, and there are so many stops ahead.