It would be depended upon how you raise the invoice as a service provider. If you are raising invoice seperately for railway transportation as well as loading , unloading i.e. cargo handling then both would be treated as different services as reference to main service doesn't include service provided for such main services. Further, in such case, concept of bundled service would also not apply. it may be noted that cargo handling service is liable at full rate of service tax i.e. 15%.
However, If you are raising the invoice only for Railway transportation service then, abatement would be applicable considering it as a bundled service. If it is naturally bundled then essential character is required to be considered and if it not naturally bundled then service would be chargeable at the rate at which it is having highest liability of service tax.