B737-800
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Situational Awareness
Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Clearance
Human Factors; Chart Or Publication; Aircraft
We were getting vectors for a visual approach to Runway 19C at IAD.  We were given a heading from Approach and cleared the visual approach to 19C then handed off to Tower.  I was slightly high on the approach so I commanded flaps 5 and squared off my base to final turn to bleed off some altitude.  I armed the approach mode.  I then called for gear down and flaps 15.  I continued the descent and caught up with the altitude I wanted to be at for the visual approach.  I looked up from the PFD (Primary Flight Display) and noticed the VOR/LOC had not captured and we were starting to fly way left of runway centerline.  I disconnected the autopilot and auto-throttles and started a right bank for the runway to centerline.  As I started the right turn we received a TCAS RA from a CRJ on approach to Runway 19L.  The Captain looked and had the CRJ in sight outside his windshield.  I started a TCAS climb and they performed a TCAS descent.  We climbed 150-200 ft. and the RA was over.  We realigned with the runway and me and the Captain determined it was safe to continue the approach.  The rest of the flight went by without incident.  At the gate we noticed on the ATIS that the Runway 19C localizer was out of service.  The flight paperwork did not have any Runway 19C localizer NOTAM published.  The Captain called Dulles Tower to clarify the events that had happened.
Radar vector to intercept ILS Runway 19C FO (First Officer) flying had called the airport insight so cleared for visual a little high when we flew through the localizer and we did get a TCAS RA climb.  FO disconnected the Autopilot and auto-throttle and climbed 150 ft. until clear of conflict.  I had the CRJ insight for Runway 19L.  Made the report to ATC of TCAS RA.  FO was now getting good signal from ILS glide slope and localizer and intercepted course and landed uneventful.  It turns out that the ILS Runway 19C was showing inoperative on the ATIS which we did miss during our brief and we confirmed that with ATC which said they were doing some maintenance on it.  I checked the flight paperwork and did not find the NOTAM for the ILS Runway 19C.  I called ATC on the ground to give them a narrative of what happened and they informed me that the CRJ also got a TCAS RA descend for 2 seconds and then landed safely.
B737 flight crew reported flying a NOTAMed localizer which resulted in a conflict with another aircraft inbound to a parallel runway.