MT-2/MT-3/ST Coupler Buffer Railway Coupler Draft Gear Assembly AAR M901E

MT-2/MT-3/ST Coupler Buffer Railway Coupler Draft Gear Assembly AAR M901E

1. Brief introduction:

The coupler buffer system is a crucial component of any vehicle. Thanks to the coupler buffer, locomotives can be connected to vehicles, and vehicles can connect to one another, enabling traction force to be passed during operation. Additionally, it helps lessen impact force when shunting or braking. This device includes several parts: the coupler, buffer (or draft gear), coupler yoke, coupler yoke pin, impact seat, and slave plates. The setup consists of the front slave plate, buffer, and rear slave plate arranged within the coupler yoke. The coupler connects with the coupler yoke through the coupler yoke pin. In summary, the coupler buffer serves three primary purposes: coupling, traction, and buffering.

2. MT-2 buffer:

The MT-2 Draft Gear functions as a friction spring buffer, boasting features like high capacity, low impedance, and dependable performance in accordance with the AAR M901E specification. This gear is used in the C63, C76, and C80 series of heavy freight cars. Additionally, it is utilized in 70t class freight cars throughout China.

3. MT-3 buffer:

The MT-3 friction draft gear is a completely steel device designed for dry friction. It was developed by learning from the successful MT-2 type buffer and is suitable for general freight cars weighing up to 60 tons.
This draft gear includes a box structure, a friction system, and an elastic component. It features a friction system made up of two wedges and two moving plates, along with a cylindrical spiral spring serving as the elastic part. The box does not participate in the friction process, and it comes pre-compressed when delivered.

4. ST buffer:

The ST draft gear is designed with a straightforward structure, being lightweight and cost-effective. It functions as a dry friction spring buffer, making it ideal for standard freight locomotives and general-purpose freight cars that weigh up to 84 tons. 
This draft gear mainly includes a friction mechanism, a main spring, and a box. Within the mechanism, three identical friction wedges work with the thrust cone and box to create three distinct friction systems. The thrust cone absorbs the impact force from the slave plate, allowing the friction wedge to glide along the box’s slope and the limit washer. The main spring is made up of an outer spring and an inner spring, which together provide high stiffness. When an impact occurs, part of the force is converted into the elastic potential energy stored in the buffer’s main spring, while another portion is used for friction work within the mechanism. After the impact, some of the elastic potential energy is spent on overcoming friction during the recovery of the mechanism, while the remaining energy is passed to the slave plate to help reduce and absorb the longitudinal impact forces.