Hello All, This may be a bit off topic. If so, my apololgies. A client of mine, a rail car storage company, has asked that I create a PHP/MySQL application in which they will maintain and track rail cars. I am having a bit of trouble however working through one of thier requirements. They need to know in what position the rail car is on each track. For example, they might have a track called X which will hold 30 rail cars. They would enter the car information for 30 cars and associate each of them with track X. If one of the car owners decides to move car 3 out of storage, then the remaining 29 cars must be re-numbered ( ie; car 1 and 2 would remain and car 4-30 would become car 3-29 ). In the same manner, I need to be able to add a car to the track once an empty slot is available. For example, If the new car goes at the front of the track then it would become car 1 and the remaining cars, originally numbered 1-29 would become 2-30. I hope I explained thourougly. Any suggestions would be appreciated. Randy