Freight car draft gears · The energy-absorbing unit behind the coupler, sized to the 24-5/8 in AAR pocket, approved to AAR M-901E and rated by travel, capacity in foot-pounds, reaction force and weight, in all-steel friction or rubber-friction designs
A draft gear sits in the pocket behind a rail car's coupler and absorbs the buff (compression) and draft (pulling) forces between cars during coupling, braking and acceleration, protecting the car body and lading. Ask three things first: which approval and pocket size the car uses, what energy capacity and travel the service needs, and whether an all-steel friction or rubber-friction design suits the duty and maintenance plan.
Draft gears for freight rail cars approved to AAR M-901 and fitted in the standard coupler pocket, in steel-friction and elastomer- or rubber-friction designs. Couplers and knuckles themselves, end-of-car cushioning units, passenger car couplers and buffers used outside AAR service are outside this page.
01
Wabtec lists its Mark 50 draft gear as AAR M901E, for a 24-5/8 in pocket with 3-1/4 in travel, AAR Rule 21 Group J, for all car types up to 286,000 lb gross rail load (286k GRL). It describes the Mark 50 as an all-steel friction gear with replaceable hardened friction plates, and as the first draft gear to receive AAR unconditional approval to M901E. [1]
Miner lists steel-friction and elastomer-friction draft gears approved to M-901E; its data sheets give an official rating travel of 3.19 in for the all-steel Crown SE and 3.05 in for the SL-76 rubber-friction gear, whose maximum travel is 3.15 in. [3] [4] [2]
Editorial calculation: a 24-5/8 in pocket is about 625 mm and 3-1/4 in travel is about 83 mm; 3.19 in and 3.05 in are about 81 and 77 mm. [1] [3] [4]
Give the supplier the car type and gross rail load, the AAR approval and Rule 21 group required, pocket dimensions, coupler and yoke arrangement, service (unit train, heavy haul, general), climate, required capacity and travel, preference for steel-friction or rubber-friction, and quantity.
02
Wabtec rates the Mark 50 at an AAR capacity of 38,940 ft-lb and a weight of 386 lb, calling it the lightest all-steel friction draft gear approved to M901E. [1] Miner's all-steel Crown SE has an official capacity of 44,980 ft-lb, an official maximum capacity of 47,520 ft-lb and weighs 359 lb, using a double-wedge friction clutch and alloy steel coil springs. [3]
Miner's SL-76 combines a friction clutch with a natural rubber spring package for heavy-haul service; it lists 47,820 ft-lb official capacity, 511,000 lb reaction force at rating travel, 53,900 ft-lb capacity at maximum travel and 314 lb weight. Each Miner data sheet shows a drop-hammer force–travel curve for compression and release. [4] [3] Compare capacities only under the same rating definitions, since makers report rated, official and maximum values.
Editorial calculation: with 1 ft-lb = 1.356 J, 38,940 ft-lb is about 52.8 kJ, 44,980 ft-lb about 61.0 kJ and 47,820 ft-lb about 64.8 kJ; 511,000 lb force is about 2,270 kN; 386, 359 and 314 lb are about 175, 163 and 142 kg. [1] [3] [4]
03
The companies in the manufacturer list below show this product on their own websites. Confirm the legal seller, factory and scope for your order.
Ask any supplier for the AAR approval certificate and Rule 21 group, rated and maximum capacity, travel, reaction force, drop-hammer curves, weight, pocket fit, friction and spring materials, service life data, reconditioning options and lead time.
04
This is a functional reference built from the sources cited; it is not one maker's specification.
| Part | Role | Fix in the order |
|---|---|---|
| Housing | Fits the AAR pocket and carries loads. [1] [3] | Pocket size. |
| Friction clutch | Absorbs energy by friction. [3] [4] | Wedge design. |
| Friction plates | Wear surfaces, replaceable on some gears. [1] | Hardened plates. |
| Spring package | Returns the gear; stores energy. [3] [4] | Steel or rubber. |
| Approval | AAR M-901E acceptance. [1] [2] | Certificate. |
05
A draft gear quotation needs values for your cars. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.
| Field | What it means and published values | Ask the supplier for |
|---|---|---|
| Coupler Type | Not stated in the reviewed sources. | Coupler and yoke. |
| Coupler Height (mm) | Not stated in the reviewed sources. | Per car standard. |
| Draft Gear Capacity (kJ) | e.g. 38,940–47,820 ft-lb (≈52.8–64.8 kJ). [1] [4] | Rated and max. |
| Draft Gear Stroke (mm) | e.g. 3-1/4 in (≈83 mm) travel class. [1] | Rating travel. |
| Maximum Coupler Force (kN) | e.g. 511,000 lb (≈2,270 kN) reaction at rating travel. [4] | Reaction force. |
| Operating Temperature (°C) | Not stated in the reviewed sources. | Range. |
| Material Grade | All-steel or steel with rubber springs. [1] [4] | Materials. |
| Weight (kg) | e.g. 314–386 lb (≈142–175 kg). [4] [1] | Weight. |
| Fatigue Life | Not stated in the reviewed sources. | Service data. |
| Corrosion Protection | Not stated in the reviewed sources. | Finish. |
06
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Cars: [type; GRL] Approval: [AAR M-901E; Rule 21 group] Pocket: [24-5/8 in or other] Capacity: [ft-lb or kJ; travel] Design: [steel-friction; rubber-friction] Service: [heavy haul; general] Quantity: [gears]
This company lists this product on its own website.
Its website lists rubber draft gears for railway couplers.
Product scope checked 2026-10-12
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
Wabtec lists its Mark 50 for a 24-5/8 in pocket with 3-1/4 in travel under AAR M901E. [1]
Sources checked 2026-10-11. Wabtec and Miner Enterprises make AAR-approved freight car draft gears.
Ask for use case, specification boundaries, supplier type, and RFQ preparation information for this product.
Compare manufacturer profiles with relevant product and process capability.