Heat vegetable oil in a large pan on medium-high until very hot. Season roast with salt & pepper. Add roast to pan, turning to brown on all sides (about 3 minutes per side)
Remove roast and place in a 6-qt crockpot. Pour out or use a paper towel to remove all but about 2 Tbsp of the meat drippings
Add the carrots, peppers, onions and garlic to the pan and saute for about 4 minutes, until the carrots start to soften.
Add the wine to the pan and use a spatula to scrape the meat bits from the bottom of the pan.
Allow vegetables and wine to simmer a few minutes, until the wine is reduced by about 1/4. Add the beef stock and heat mixture until simmering
Pour mixture over roast in the crockpot. Add rosemary, bay leaves, tomatoes and tomato sauce
Cook for 4-5 hours on high or 6-8 hours on low
Transfer roast to serving platter and pour some of the sauce created in the crockpot over the roast.
Serve over egg noodles or mashed potatoes.