Slow and tiring. How to understand?

Question

In a book in the section of related vocabulary (describing weather section) they provided some useful phrases and here's one of them:

pace of journeys slow and tiring

Here's how I understand what it might mean. We could say

I'm going to take a nap as soon as we get back home. The pace of our today's journey was really slow and tiring.

First of all, does it sound correct? If so, am I right in thinking that slow and tiring here means with low speed and boring so we get tired. I'm actually confused by the fact that there two completely unrelated adjectives. Slow is about speed and tiring is about your feeling.

And here in the phrase (pace of journeys slow and tiring) pace already means speed. It's difficul to imagine how pace might be tiring, really...

Answer 1

You are overthinking the meaning of the adjective "slow". Let's say there is a bullet train which can run at 300 km per hour and there is a very slow train with the maximum speed of only 50 km per hour. Which train do you think would make you more tired? Of course, a slower train would make you more tired as it takes more time to reach one place from another.

You should understand the phrase as follows:

Pace of journeys is slow. Since it is slow, it makes you feel more tired than when the pace is faster (less slow). That's why the pace is tiring.

Tiring means:

Causing one to need rest or sleep.

Answer 2

Tiring is not a feeling; tired is.

The pace of the journey is tiring.
= The pace of the journey is making you feel tired.

On a more general note:

The pace of the journey is slow and tiring.
= The pace of the journey is so slow that most people will feel tired.
= The slow pace of the journey can make people feel tired.