Here a network of mini railways and train stations(which correspond to the users' delivery points) can be used to deliver goods to people in urban areas without having to be delivered by a human as it is done in most cases today. Delivering goods that are not very heavy or big will require less energy and money if such a system is implemented.
The idea is to build a network of conduits that will convey small packages through the city. the packages can be moved along the lines of the mini railway network. The little courier packages will be attached to small vehicle bases that are powered electrically through the railway's lines. Most of the network can be underground. Once the dock is loaded with the package for delivery with the user's address, the package will be delivered to the user's house or doorstep.
How is this better than other courier services?
Current automated delivery ideas involve using drones or commuter robots. The proposed idea will result in less cost and complexity per transport unit. This is because the individual devices are autonomous and designed to be robust. The proposed system can be controlled from one main server to give a better economy of resources. An additional advantage is that the weight that has to be transported is slightly more than the package's weight unlike cases where a human will have to be transported along with a package to deliver it.
Possible challenges of the proposed system
Constructing the system's main network of conduits will cost a lot of money. I believe the money invested will be made back over the first few years that the network is operational.
The routes of the conduits: The most efficient routes will usually go through a lot of private property and a lot of paperwork will have to be sorted.
The risk of damaging fragile goods because there is no human to supervise the transport. This can be solved by transporting such goods at lower speeds and special packaging can be constructed to reduce the risk of damaging fragile goods.