Class “N” – Caboose – The Martin Family

Sensing, audio, emergency braking unit (CDU) that accepts, analyzes and displays information relevant to the rear of train
The NA provides audible alerts and displays to assist the engineer operating the train and is equipped with emergency braking feature in the event normal brake capability is lost
The arming feature prevents unauthorized use of the emergency braking device (4/99)

Receiver Display Unit (RDU)
A device mounted on the control stand in the locomotive to receive, analyze and display information as transmitted by the SBU
The RDU provides audible alerts and displays to assist the engineer in train operation (4/99)

Communications Logic Unit (CLU)
A device located in the short hood of the locomotive which accepts and analyzes radio messages transmitted from the rear of the train by the SBU
After the messages are analyzed the CLU forwards the information for display in the cab of the locomotive (4/99)

Input and Display Unit Unit (IDU). A device mounted on the control stand in the cab of the locomotive to display information which has been sent by the SBU and analyzed by the CLU
The IDU provides audible alerts and displays to assist the locomotive engineer in the handling of the train (4/99)

Caboose mounted on eight wheels and longer than four-wheel caboose, but of the same general design (1/17-10/66)
All cabooses (1/73-4/99)

A device mounted on the trailing coupler on the rear car of the train coupled to the brake pipe
The SBT senses brake pipe pressure, and may sense motion and direction. This information is relayed by radio to the head end of the train to a RDU, CDU or a CLU/IDU combination
In addition, the SBT acts as a marker to locate the rear of the train and is equipped with an emergency braking feature to be used in the event of a loss of the normal braking capability from the head end of the train (4/99)

Light only, may have brake pipe pressure device (NLU) mounted on side of trailing coupler on rear car
The NLU may or not be coupled to the brake pipe. When coupled senses brake pipe pressure, and displays this information on a mechanical gauge on the side of unit
Primary function is to act as a marker to indicate the rear of train (4/99)

Freight train service caboose for convenience of trainmen. This caboose is mounted on four wheels and has lookout at top over roof. It is fitted with bunks or benches and a stove for cooking and heating purposes, also tank for storage of drinking and washing water, and small tool storage boxes (1/17-10/66)

Sense and Braking Unit (SBU)
A device mounted on the trailing coupler on the rear car of the train and coupled to the brake pipe
The SBU senses brake pipe pressure, and may sense motion and direction
This information is relayed by radio to the head end of the train to a RDU, CDU or a CLU/IDU combination
In addition, the SBU acts as a marker to indicate the rear of the train
The SBU is NOT equipped with an emergency braking feature (4/99)

Class “N” – Caboose