I last wrote about the Rolls-Royce (LSE:RR) share price in early July. It was hovering at around £4.60 then. I came to a verdict that its shares would stay near this mark until the end of 2024.

How wrong I was. Its shares have grown by almost 20% since then, with a price of £5.55 at the time of writing (30 October).

Since the start of the year, its shares have climbed by 86%.

If I’d invested at the start of 2023, I would have had a return of 495%.

Its clearly one of the best investments that could have been made over that period.

What’s been pushing the share price up?

To explain the share price growth, we simply need to look at its half-year results for 2024. Rolls-Royce has been experiencing strong growth for a while now. For example, its profit before tax has almost doubled to £1.04bn in the first half of 2024 from the same period in 2023.

Furthermore, the company is getting involved in exciting projects. The Czech Republic’s state utility company recently selected Rolls-Royce for its small modular reactor (SMR) programme. This market is expected to be valued at £295bn by 2043. This shows the company has further growth prospects, helping to fuel its share price.

This FTSE 250 company could emulate such a return

The problem with investing in Rolls-Royce right now is that it’s becoming a riskier investment. It’s currently trading at a forward price-to-earnings (P/E) ratio of 28, meaning that its shares are quite expensive.

Because there’s a lot of optimism already baked in, its shares could prove fragile in the presence of bad news. For example, further escalation of conflicts in the Middle East could adversely affect oil prices, which could hurt the wider economy and also the company’s earnings.

That’s why I’d turn my head to Trainline (LSE:TRN).

The FTSE 250 company has returned a strong but comparatively much less glamorous return of 20% in 2024.

However, it’s forward P/E of 22 makes its shares much cheaper.

But I think there are plenty of other reasons to like the company aside from this.

Notably, it’s growing very well. In its latest half-year results for FY25, the company saw its net ticket sales rise by 14% year on year to reach £3bn. Moreover, this translated to revenue growth of 17% to hit £229m.

There’s also huge international potential. This is evidenced by encouraging growth in Spain and Italy, which saw net ticket sales up by 23%.

I am concerned about the company’s dependence on carrier competition, however. Trainline’s services are rendered redundant when carrier competition is low. Therefore, if competition declines in the railway sector, its business could be put into jeopardy.

Now what?

Trainline is growing well and is in fact Europe’s most downloaded rail app. I also believe that as the shift towards digital train tickets as opposed to paper tickets continues, the company can experience accelerated growth going forward.

That’s why I see it generating Rolls-Royce level returns over the long run. It’s also why I’ll continue to buy its shares.