Combined transport is like when you want to go on a camping trip but your tent, sleeping bag, and food are too heavy to carry in your backpack. So, you decide to bring a big car with you to carry everything. This way, you can hike to the camping spot with your light backpack, while the car follows you on the road carrying all the heavy stuff.
In real life, combined transport means using different types of transportation to move goods from one place to another. For example, if a company wants to move a lot of products from one city to another, they might use a truck to bring the products to a train station, and then put the products on the train to continue their journey. This saves time and money because trains can carry a lot more products at once than trucks can.
So, combined transport is like teamwork for transportation. Different transportation modes work together to get your stuff where it needs to go, just like how you work with your friends to carry all your camping gear on a trip.