What are the two ways in which an interlocking system can be arranged?

y preparing two set of accounting records,

1)Financial accounting Record 

2) Cost accounting Records of accounts

In railway signalling, an interlocking is an arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as junctions or crossings. The signalling appliances andtracks are sometimes collectively referred to as an interlocking plant. An interlocking is designed so that it is impossible to display a signal to proceed unless the route to be used is proven safe.

Interlockings can be categorized as mechanical, electrical (electro-mechanical or relay-based), or electronic/computer-based.

Mechanical interlocking

In mechanical interlocking plants, a locking bed is constructed, consisting of steel bars forming a grid. The levers that operate switches, derails, signals or other appliances are connected to the bars running in one direction. The bars are constructed so that if the function controlled by a given lever conflicts with that controlled by another lever, mechanical interference is set up in the cross locking between the two bars, in turn preventing the conflicting lever movement from being made.

Electro-mechanical interlocking

Power interlockings may also use mechanical locking to ensure the proper sequencing of levers, but the levers are considerably smaller as they themselves do not directly control the field devices. If the lever is free to move based on the locking bed, contacts on the levers actuate the switches and signals which are operated electrically or electro-pneumatically. Before a control lever may be moved into a position which would release other levers, an indication must be received from the field element that it has actually moved into the position requested. The locking bed shown is for a GRS power interlocking machine.