The stand IMHO as an engineer is more than capable of handling 2400 lbs. Each 2x4 can take about a 5000 lbs load on end without splitting, depending on construction techniques.
The ONLY concern I do have is that the cross braces do not have a 2x4 under the ends, so that they must distribute their load through the nails/screws to the vertical 2x4. As viggen stated, you may want to put a second 2x4 under each vertical column to take the load of the 2x6 at the ends. Also, you may want to add another 2x6 cross member where the other vertical 2x4 columns are and do a similiar vertical 2x4 arrangement 9ege two 2x4, one of which is under the 2x6 to take its load). I would be more concerned for long term strength, not on initial fill.
Most people here tend to overbuild their wood stands (myself included). Also, I'd be concerned about preserving the wood. I used an oil based primer and epoxy to completely seal the wood and make it waterproof. Just my 2 cents...
HTH
Bryan