The Series 4000 is a spring-loaded fabric rail enclosure available in a three or four-sided configuration. It is designed to encapsulate the space between the building opening and a rail car to ensure weatherproof protection to the dock area.

Once the rail car is in position, spring tension extends the fabric enclosure, maintaining pressure against the side of the vehicle. Our superior performance Dynaflex fabric will greatly increase this unit's life expectancy.

Series 4000 Alternate
Series 4100 - 4 Sided Frame, 3 Sided Cover
Series 4200 - 4 Sided Frame, 4 Sided Cover

Suggested Specification:
Cover fabric to be Dynaflex, or other fabric as specified. Frame members, 2" x 6" header and 2" x 8" sides to be pressure treated wood, kiln dried before and after treating. (Steel frames are optional.) Unit to include upper and lower spring bias tension arms of 1" I.D. galvanized pipe, which are designed to extend the unit and maintain pressure against the rail car. The tension arms and the top crossbar, upon release of the rope/pulley system, shall have horizontal and vertical movement provided by the means of self lubricated steel trolleys rolling in steel formed tracks. Unit to include fabric tie backs equipped with touch and hold to maintain unit in the retracted position.

The head curtain shall have two vertical splits, held together with touch and hold, to allow for it to be attached to the interior of the rail car to form a natural canopy. Adjustable rubber cords are provided as a means to make the attachment of the head curtain to the rail car.

Here's how a performance based specification would be written:

FABRIC: Dock seal or shelter shall incorporate a Dynalon cover having the characteristics listed below. All bidders must submit certified test results with bid. The manufacturer shall state the characteristics of the fabric offered and that all tests are done in accordance with Federal Standard 191 and the specific method as listed below. Wear characteristics of any substitute material shall meet or exceed performance specifications.

Summary of properties of fabrics per Federal Standard 191

Coated Fabric: Dynalon
Tear strength (Per Lbs., Method 5134): 300 x 300
*Abrasion Resistance (Cycles, Method 5306): 6000
Tensile Strength (Per Lbs., Method 5100): 1200 x 1200
Cold Resistance (At -40°F, Method 5874): Pass

Coated Fabric: Dynaflex
Tear strength (Per Lbs., Method 5134): 165 x 165
*Abrasion Resistance (Cycles, Method 5306): 1250
Tensile Strength (Per Lbs., Method 5100): 550 x 575
Cold Resistance (At -40°F, Method 5874): Pass

*H-22 Wheel, 1000 Gram Load, End Point-First Exposure to Base Fabric